Zotac GeForce GT 640 DDR3 Review: Glacial Gaming & Heavenly HTPC
by Ryan Smith & Ganesh T S on June 20, 2012 12:00 PM ESTFinal Words
Bringing things to a conclusion, when Ganesh and I began working on reviewing the Zotac GeForce GT 640 DDR3 we set out with two cards and two different goals. I would take a look at gaming performance and physical characteristics while Ganesh would be free to focus on the HTPC side of things. Unsurprisingly we have come to two very different conclusions.
From a gaming standpoint the GeForce GT 640 is unremarkable if not flat-out bad. NVIDIA’s GK107 GPU may have a lot of performance potential, but its first desktop iteration as the GeForce GT 640 DDR3 does not. The decision to equip it with DDR3 clearly bottlenecks the card just as it has done to previous generation entry-level cards. So this is by no means a new problem, but it’s a recurring problem that always has the same solution: buy GDDR5. With that said, NVIDIA and their partners will no doubt sell GT 640 DDR3 cards by the truckload – make no mistake, having lots of VRAM moves lots of cards – but if you’re fortunate enough to be reading this article then you’re probably well aware of the performance difference between DDR3 and GDDR5.
As a result of the decision to equip the GT 640 with DDR3, compared to every other major card around $109 including the 7750, 5750, GTS 450, and GTX 550 Ti, the GT 640 is the slower card and typically by quite a bit. Even if we look at the much narrower range of sub-75W cards, AMD’s 7750 has the clear upper hand in gaming performance. As it stands there’s just no good reason to get a GeForce GT 640 if you intend to game on it. A Radeon HD 7750 performs far better for the same price and effectively the same power consumption, and that’s really all there is to it.
This brings us to the second conclusion: HTPC usage. To some extent HTPC tasks are still reliant on memory bandwidth – post-processing in particular – but overall the measure of a good HTPC card is rooted in its features and power consumption rather than its raw performance. To that extent the GeForce GT 640 is nearly everything we expected from the moment we saw GK107. 4K video decoding via VP5 and 4K over HDMI are working, custom resolution/timings are working, there’s enough processing power to handle everything short of intensive madVR use-cases, and all of this is on a sub-75W card. While NVIDIA still has some room to grow and bugs to fix, at this point it’s certainly the best HTPC card we’ve tested yet.
Really the only thing we don’t have a good handle on for HTPC usage right now is video encoding through NVENC. We’ve already seen NVENC in action with beta-quality programs on the GTX 680, but at this point we’re waiting on retail programs to ship with support for both NVENC and VCE so that we can better evaluate how well these programs integrate into the HTPC experience along with evaluating the two encoders side-by-side. But for that it looks like we won’t have our answer until next month.
Wrapping things up I’d like to spend a few words on the Zotac GeForce GT 640 design in particular. Zotac has worked themselves into an interesting position as the only partner currently offering a single-slot card, and while the fan noise will probably drive some customers away it certainly fulfills its role well. Unfortunately for Zotac the mini-HDMI port problem we outlined earlier is a direct obstacle for the GT 640’s greatest strength: HTPC usage. It’s by no means an insurmountable problem, but it makes the Zotac card a poor out of the box HTPC product. Once Zotac resolves the issue they’re going to have among the finer HTPC cards available, but until then prospective HTPC customers will need to take extra care to mitigate the issue.
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cjs150 - Thursday, June 21, 2012 - link
"God forbid there be a technical reason for it.... "Intel and Nvidia have had several generations of chip to fix any technical issue and didnt (HD4000 is good enough though). AMD have been pretty close to the correct frame rate for a while.
But it is not enough to have the capability to run at the correct frame rate is you make it too difficult to change the frame rate to the correct setting. That is not a hardware issue just bad design of software.
UltraTech79 - Wednesday, June 20, 2012 - link
Anyone else really disappointed in 4 still being standardized around 24 fps? I thought 60 would be the min standard by now with 120 in higher end displays. 24 is crap. Anyone that has seen a movie recorded at 48+FPS know whats I'm talking about.This is like putting shitty unleaded gas into a super high-tech racecar.
cjs150 - Thursday, June 21, 2012 - link
You do know that Blu-ray is displayed at 23.976 FPS? That looks very good to me.Please do not confuse screen refresh rates with frame rates. Screen refresh runs on most large TVs at between 60 and 120 Hz, anything below 60 tends to look crap. (if you want real crap trying running American TV on an European PAL system - I mean crap in a technical sense not creatively!)
I must admit that having a fps of 23.976 rather than some round number such as 24 (or higher) FPS is rather daft and some new films are coming out with much higher FPS. I have a horrible recollection that the reason for such an odd FPS is very historic - something to do with the length of 35mm film that would be needed per second, the problem is I cannot remember whether that was simply because 35mm film was expensive and it was the minimum to provide smooth movement or whether it goes right back to days when film had a tendency to catch light and then it was the maximum speed you could put a film through a projector without friction causing the film to catch light. No doubt there is an expert on this site who could explain precisely why we ended up with such a silly number as the standard
UltraTech79 - Friday, June 22, 2012 - link
You are confusing things here. I clearly said 120(fps) would need higher end displays (120Hz) I was rounding up 23.976 FPS to 24, give me a break.It looks good /to you/ is wholly irrelevant. Do you realize how many people said "it looks very good to me." Referring to SD when resisting the HD movement? Or how many will say it again referring to 1080p thinking 4k is too much? It's a ridiculous mindset.
My point was that we are upping the resolution, but leaving another very important aspect in the dust that we need to improve. Even audio is moving faster than framerates in movies, and now that most places are switching to digital, the cost to goto the next step has dropped dramatically.
nathanddrews - Friday, June 22, 2012 - link
It was NVIDIA's choice to only implement 4K @ 24Hz (23.xxx) due to limitations of HDMI. If NVIDIA had optimized around DisplayPort, you could then have 4K @ 60Hz.For computer use, anything under 60Hz is unacceptable. For movies, 24Hz has been the standard for a century - all film is 24fps and most movies are still shot on film. In the next decade, there will be more and more films that will use 48, 60, even 120fps. Cameron was cock-blocked by the studio when he wanted to film Avatar at 60fps, but he may get his wish for the sequels. Jackson is currently filming The Hobbit at 48fps. Eventually all will be right with the world.
karasaj - Wednesday, June 20, 2012 - link
If we wanted to use this to compare a 640M or 640M LE to the GT640, is this doable? If it's built on the same card, (both have 384 CUDA cores) can we just reduce the numbers by a rough % of the core clock speed to get rough numbers that the respective cards would put out? I.E. the 640M LE has a clock of 500mhz, the 640M is ~625Mhz. Could we expect ~55% of this for the 640M LE and 67% for the 640M? Assuming DDR3 on both so as not to have that kind of difference.Ryan Smith - Wednesday, June 20, 2012 - link
It would be fairly easy to test a desktop card at a mobile card's clocks (assuming memory type and functional unit count was equal) but you can't extrapolate performance like that because there's more to performance than clockspeeds. In practice performance shouldn't drop by that much since we're already memory bandwidth bottlenecked with DDR3.jstabb - Wednesday, June 20, 2012 - link
Can you verify if creating a custom resolution breaks 3D (frame packed) blu-ray playback?With my GT430, once a custom resolution has been created for 23/24hz, that custom resolution overrides the 3D frame-packed resolution created when 3D vision is enabled. The driver appeared to have a simple fall through logic. If a custom resolution is defined for the selected resolution/refresh rate it is always used, failing that it will use a 3D resolution if one is defined, failing that it will use the default 2D resolution.
This issue made the custom resolution feature useless to me with the GT430 and pushed me to an AMD solution for their better OOTB refresh rate matching. I'd like to consider this card if the issue has been resolved.
Thanks for the great review!
MrSpadge - Wednesday, June 20, 2012 - link
It consumes about just as much as the HD7750-800, yet performs miserably in comparison. This is an amazing win for AMD, especially comparing GTX680 and HD7970!UltraTech79 - Wednesday, June 20, 2012 - link
This preform about as well as an 8800GTS for twice the price. Or half the preformance of a 460GTX for the same price.These should have been priced at 59.99.