Zotac GeForce GT 640 DDR3 Review: Glacial Gaming & Heavenly HTPCby Ryan Smith & Ganesh T S on June 20, 2012 12:00 PM EST
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.