Thanks for sharing this. I recently tested both and experienced the same. Also found the 780 screen much less sensitive; and had difficulty with the awkward resetting & re-calibrating steps; unlike the 680 which had that as a hard reset button and a re-calibrate function. The 780 does have some nice new functions like "where am I", routes, and the MSN live map "send to GPS". Both are great GPS; quite a toss-up especially with the 780 costing at least $200 more than the 680.

Awesome! Thanks a lot for posting this. I love this site. You always give me more information to share with customers. Thanks!

Hi Fletch will the Nuvi 880 have the same system as the 780 or will they go back to the nuvi 600 series antenna. Also does The 880 offer most use of freeways and least use of freeways along with fastest and shortest route. This would help tremendously so that the Nuvi does not take me off the highways, it seems to do that alot. then it puts you back on afer going thru some side roads with a whole lot of lights. Thanks in advance.

How about old Streetpilot C550? Is it weeker than those Nuvi models? Also it doesnt have external antenna.

Some constructive criticism:

1. Have you confirmed that the signal strength scales are the same on different units? These are arbitrary numbers.
2. The pictures show the units in different window locations. Were they compared in each location?
3. The 780 show it has signal lock on 9 birds and trying for the 10th. The 680 (or is it a 660??) shows a lock on 8 and trying for the 9th. The 680 (660?) misses the two birds at the eastern and western horizons entirely.

The biggest problem is that you have attempted to correlate signal strength to "accuracy". You need to compare the two units with an exact known location, like a USGS bench mark.

Fletch

Thanks for performing the side by side GPS receiver test.
May I recommend next time you test the GPS further apart since having GPS next to each other can cause some signal issues at times.
We know if one is to close to a radio tower or transceiver antenna, it can cause GPS RF signal to act up and give poor reading. We first found this out back in 1995 with the Rockwell PathMaster, when we mounted the external GPS antenna near a two way radio antenna, it use to blow the Rockwell GPS receiver out.

As far as Garmin GPS receiver goes, I think they are also taking some cost cutting steps to compete and what we get may not be the best they have to offer.

I am pretty sure the C550 GPS receiver is a SiRF StarIII which should function as well as the Nuvi 3xx and 6xx.

The Nuvi 8xx will not have a flip out antenna since they were breaking off a lot and a cause of returns for Garmin.

I am wondering how Garmin will be addressing the future of pedestrian mode routing feature where one can route inside a shopping mall possibly? Since most would use the PND pedestrian mode under over pass or even in shopping centers. I feel Garmin should really consider using the SiRFDiRect receiver chip with the Dead Reckoning feature or something comparable.

Garmin has selected not to show who or what GPS receiver they are including in their PND units so they can switch mid stream and no one can complaint about it.

Listed only as high sensitivity GPS receiver covers a broad range of GPS receiver including Garmin own GPS receiver.

About 4 years ago, I told Garmin their GPS receiver was inferior to SiRF and they should consider using the SiRF GPS receiver, at that time, they stated they are Garmin and will never consider using their competition GPS receiver.
Now I guess they are going back to trying to use their own high sensitivity GPS receiver, got to give them an A for trying!

Garmin is a great company and I am thankful that they are trying hard to offer a great PND for our consumers.

Just purchased the 750. Came across some interior settings that the public may not be aware of. At the "Menu" page (Where to? View Map) If you hold your finger on the battery status bars for approx. 8 seconds, you get detailed information regarding the device such as:

SW Ver
ROM and RAM results
Time in hours mins and seconds.
Freq.
Temp1
Temp2
Batt Capacity and etc..
Just click "Next" to toggle through. When you exit, it reboots the device.

As well, I was told by a Gar Rep. that 7XX and 8XX units do not operate WAAS. I asked why, they replied "The chips in the units are more sensitive to accuracy, so therefore no need for WAAS.

Umm, wait a second here. How can the "accuracy" number even be correct? If the unit could know how far it's off by then this by definition means that it's not off at all. It would have to know it's precise location in order for the accuracy number to be well... accurate.

I don't see how this is a meaningful comparison given that and the fact that we're talking about 7 feet here. Isn't that well within the error tolerance of a non-military or aviation grade GPS reciever?

Garmin's "accuracy" figure is based on a model that indicates a 50% chance that the location is within a circle of the accuracy figure shown. For a certainty of approx 98%, multiply by 2.3. There is no 100% accuracy for any consumer device or industrial device

for what it is worth. I was reading this article and decided to get out my new Nuvi 760 and try it. I am inside an 8 story building on the second floor. My office is in the middle of the building and when I turned on my 760 I was locked on to 11 satelites within @ 30 seconds with an accuracy of 18 ft.

Know what Dan? The TT and Magellan guys won't ever believe it. You'll see a post before long about how much faster their units lock compared to our flawed 700's.

I recently emailed Garmin support because I was wondering if they really used SIRF III chipsets in their 7xx line of receivers. The answer I got back was:

" Thank you for contacting Garmin International.

The nüvi 750 (or 760) may or may not ship with the SiRF Star III chipset installed. We do have a proprietary chip that we use as well. However, we have not discerned any operational differences between the differing chipsets that may ship within the nüvi 750. No matter which GPS chip is in the system, the nüvi is expected to work as designed. All nüvi 7xx series units may have either set installed."

This answer was enough to steer me clear of purchasing a 7xx receiver. I'm not willing to take performance risks with a company that is focused on cost-cutting against proven technology.

Tell you what. . . $100 reward for the FIRST confirmed bravo chip in a nuvi 700. My money's safe. There isn't one. What Garmin is saying, and what nearly ALL manufacturers say, is that they reserve the OPTION of changing chipsets as they or the market dictates. TomTom, Magellan, and all other major players have the same policy.

Tell you what. . . $100 reward for the FIRST confirmed bravo chip in a nuvi 700. My money's safe. There isn't one. What Garmin is saying, and what nearly ALL manufacturers say, is that they reserve the OPTION of changing chipsets as they or the market dictates. TomTom, Magellan, and all other major players have the same policy.Ever hear of a Hammerhead chip? TomTom started using it without notice a while back. Since then it was found to outperform the sirf chipset for that device. Ever hear of MTK? Garmin started using it in some of the 200 series nuvi without notice, and again it's been determined to outperform the sirf in those devices. It's old school to think that sirf is the only source for quality gps chipsets.

Warren,

GPS lock depends on whether you trapped behind athermic windows or not.

Neither an ipaq 310 or TT 920 will get signal at my desk which is directly beside and outside window.
Triple glazed athermic window kills all signals!

Appreciate you noting that Infama.

I think the question is not if the manufacturers are using SiRF as much as how well your GPS receiver is functioning when you need it?

I for one as a GPS reseller for over 12 years have experience customers coming back with Garmin products with issues regarding GPS acquisition or lack of it, this was a none issue prior to the change from SiRF to now “ High sensitivity GPS receiver” Meaning a grab bag of do you feel lucky today?

When I confront Garmin with some of the issues we are experiencing, they tell me that they are working on a software fix and for us to make sure our customers keep the unit on for about 30-45 minutes during initial use to get a solid lock on the GPS signal before turning the unit off.

If Garmin is not experiencing any issue, the tech support would not have offered such recommendations would they?

Again, SiRF is not really SiRF anymore since they purchased Centrality. TomTom did make known that they were using the Hammer Head GPS receivers over a year ago by Global locate. I have not had much negative experience with customers brining unit back because it did not lock on to GPS for over 30 minutes but for what is worth, the Hammer Head receiver was used mostly in the TT ONE and TomTom did admit that although the receiver function almost as good as SiRF it had a longer TTFF issue. But if no one complaints because it’s a affordable GPS unit than they have achieved what they set out to do which is reduce over all cost so they have more market share.

Magellan will also being using a form of SiRF but lower price receiver developed by Centrality.

I think we should focus if the product perform as advertise, and it's funny that the general perceptions is SiRF is the only answer for GPS receiver much like Garmin is the only GPS unit to own if you wish to have a reliable unit.

I would look back at history and think this one through if I was Garmin.

1] Magellan had over 50% of the market only a few short years ago with a PND product named Road Mate 700, excellent product but expense to manufacturer. Using the NavTeq Sdal format, the unit was solid and routed properly and POI search feature was also dependable.
They chose to develop their own software and changed the hardware, did not retain the NA market share due to being out of position with their low end Magellan RoadMate 300, 500, 3000 which they can’t give away and Garmin took the market share over.

2] Garmin had a successful run delivering a product that is superior to what Magellan has to offer and controlling about 50% of the NA market share with their street Pilots and Nuvi series, now they are experience stiff competition and have to make due with the lowest price hardware to compete. For the first time TomTom actually have higher market share in NA than Garmin this Q4, it was a short run due to cost reduction by TomTom, but nevertheless, Garmin is found to be vulnerable.

It's funny, but I would have a hard time if I was to buy a car and they don't advertise what size engine or tires it comes with, and who the manufacture was. I think Honda use to put a Mazda engine in some of their SUV they sold and Ford also used Mazda engines in their vans. I would say most consumers was not aware of this fact and felt they have been taken advantage off. If these new “High sensitivity GPS receivers” is so good, why are they not advertising the specs and showing the brand name of the GPS receiver they are including is superior than the SiRF they had before.
Answer: They are putting in anything they can get the best deal for, so one may have a great GPS receiver and tomorrow you buy another one and it will not be the same performance.

Answer: I think in most cases Garmin may not be showing what they are putting in these products because they cost less. TTFF is not as good in some cases and for those that never used a PND before. They would never know the difference.

Is the old saying, "IS GOOD ENOUGH" and not the Best it has to offer that Garmin and every other GPS manufacturers are delivering to us due to the low price point demand from most consumers! Hey, it’s only costing $50-$75 these days to manufacturer a PND unit, they have to cut corners anyway they can to make their 40% margin.

This year they project sales of 21-22M PNDA units in NA, and there are still tons of first time user that will be thankful if the GPS they purchased will route them to where they need to go and don't expect much more than that.
Heck for less than $150, I hope they don't expect anything more either.

GPS4ME,

All we are asking for is a high quality range from each manufacturer for the cogniscienti. They can charge a bit more for it, but at least we will know whatt to expect.

They all can have mass mkt loss leaders, mid-priced no-frill navigation beasts and higher priced gimmick models with the voice recognition, etc.

The mid and high price units should have predictable innards.

BTW, you speak of inferior Centrality stuff, but the TITAN is better than anything else at Sirf on the market today (with 40 channels and 2million effective correlators).

As for Fletch, how comes he is not reviewing fun stuff like the HP iPaq 310???? Non-newbies are intrigued by the potential of this unit.

All Nuvi 700 series do have an external antenna rear jack. If using an external antenna, placed on the roof or rear trunk of a vehicle, the reception weakness of the 780 may no longer be an issue! Any comments?

Is this an issue of signal reception, or capability to determine position accurately. If it's the latter, then it doesn't matter how good your antenna is. You still won't do as well. Does it have something to do with WAAS?

I'm currently trying to make a decision: 750 or 660. Price is about the same. If a thought a future upgrade might fix the accuracy issue, I'd go with the 750. It seems to have some nice features. Otherwise I'd go with the 660. Any comments or info would be helpful.

This is no "accuracy" issue that I've noticed with the 760. WAAS doesn't figure into the equation at all. WAAS is useless for highway navigation. The test, as done for this review, shows little.

I am trying to make a decision between getting the nuvi 680 or the nuvi 780. I am a little nervous after reading this review since the newer nuvi 780 has less accuracy and the older nuvi 680 has better accuracy. But here's the thing: I heard that the antenna on the older nuvi 680 could snap/break off. But I'm more worried about the reception and the accuracy of the nuvi 780. Any suggestions?? Please help!!!! I know that the 780 is like $80 more but I would still buy it. Also, on the 780, does the icon/car move smoother along the map than the 680?????

The accuracy of the 7xx Nuvi is much worse than the 6xx Nuvi.

This is from my personal experience. I owned the Nuvi 660 (it was stolen). I now own then Nuvi 780.

With the 780 my own address location is off by nearly 1400 feet (a solid 1/4 of a mile) [ 5280 feet in a mile ]. The Nuvi 660 was spot. This is very significant in being less accurate for the Nuvi 780. In general (for me in the LA, CA area and in Minneapolis, MN area), the Nuvi 780 is off by 1200 t0 2200 feet compared to the Nuvi 660. ( 1/4 mile or more)

Now image driving 70 MPG in Long Beach, CA and the LAX Area with the Nuvi 780 being off by 1/4 mile giving directions.

The Nuvi 780 would miss turns; tell you to turn when you should not. The less accurate (more gimmick based) Nuvi 780 is not a good GPS unit for accuracy.

The navigation on the 780 is also less accurate in that it would tell you to turn left on a road that you need to continue straight because the road turns into a new road name.

Very disappointed in the Nuvi 780 ... I hope the 8xx series is more accurate or the rumored Software Updates for the 7xx Series fix the accuracy. I hope Garmin brings back the accuracy of the 6xx series.

The "nice" features of the 780 are cool --- however a GPS-Navigator still needs to be accurate. This is the primary purpose of a GPS is navigation accuracy. Otherwise just follow the signs on the road.

The Nuvi 660 was very accurate. It new my address spot on driveway. All other point were within 30 feet (not off by 1400 to 2200 feet like the Nuvi 780). This is comparing the same addresses with the 660 and 780.

I really get a kick out of people who have no idea how consumer GPS works getting all worked into a tizzy over an imaginary number.

"Accuracy" as displayed by consumer GPS units is a very vague number. In the real GPS world, it means nothing. The real statistic that affects accuracy is GDOP, or geometric dilution of precision - which is mostly affected by a factor that the receiver has no control over - the position of the satellites. The closer the birds, the higher the GDOP - the more angular separation between the sats, the lower the dilution. Other positional error is caused by multipath reflections, ionospheric distortions, Doppler shifts, and timing errors. Mobile units primarily use the WAAS system to correct time and ionospheric distortions, and ground-based precision systems will use DGPS (differential) using a known fixed point to provide corrections within a certain radius of the diff transmitter.

The "accuracy" number is initially based primarily on GDOP, and then adjusted by the range of position samples calculated by the receiver. How each manufacturer displays this information is proprietary, and it sometimes varies even from model to model depending on how many data samples are retained in memory. The baseline for accuracy readings is generally about 50% - half of the data points sampled fall within the accuracy circle, half don't. Being as DOP and "accuracy" are primarily determined by sat geometry, the difference in number of birds locked in can greatly affect this number - and more is not always better. A difference of one sat in the GPS constellation can greatly affect the GDOP. The "accuracy" difference in the screenshots is not likely to be because of the receiver inherently, but because they're obviously locked into signals from different birds, resulting in a different GDOP result.

Doc, nice of you to post the background detail. For consumer use tho, if you want to be as sure of your position as is reasonable, it's more a matter of knowing what the "accuracy" statement of your device is really showing. On a Garmin nuvi, it's reportedly based on CEP (circular error probable), meaning there's a 50% chance that your actual position is within a circle radius of the stated accuracy and 50% that it is not. To get to a 98% (approx) certainty, simply multiply by 2.55. The issue with comparing accuracy between different manufacturers is that some use less strict methods, for instance 1 sigma, supposedly used with some(earlier?) Magellan models, allowing them to show a greater accuracy than others. Some Lowrence models have supposedly used 2 sigma, a more stringent reporting method. Trying to determine who uses what is near impossible. Without that knowledge it's unreasonable to compare reported accuracy figures between manufacturers with any certainty. But within a manufacturers model line, IMO is quite proper to compare between models as it's very unlikely a different reporting method is used.

I just purchased the Garmin 750 GPS this past week and put it to use this past weekend. When I first hooked it up, my vehicle was in the driveway of my home and the icon of the vehicle on the map was off my house by what appeareed to be a 200 feet or so and the signal strength for Sat's had all bars lit up. I then drove around the block and upon returning the car icon was spot on to my drivway. Using the unit to navigate to two Nassau county towns on Long Island New York the unit was spot on to the address number of the destinations. Although my use has been minimal the 750 seems to be a very accurate GPS unit.