Zotac GeForce GT 640 DDR3 Review: Glacial Gaming & Heavenly HTPC

HTPC Aspects : What is New?

We covered discrete HTPC GPUs in detail last year, and noted that the GT 520 was the sign of interesting things to come from NVIDIA.

The GT 520 was the first GPU from NVIDIA to come with support for VDPAU Feature Set D (also called as VP5 by some). VP5 is faster than VP4 and also brings support for decode of 4K x 2K videos. Unfortunately, the GT 520 didn't have the necessary hardware to output 4K resolution over any of its video outputs. The number of shaders in the GT 520 was also too low to support advanced deinterlacing algorithms. On the whole, despite the updated video processing engine (VPU), we couldn't recommend the GT 520 as the ideal discrete HTPC GPU.

All our concerns were supposed to be laid to rest with the launch of the Kepler series. NVIDIA started off at the high end with the GTX 680, a card which couldn't be called HTPC-friendly by any stretch of imagination. The more HTPC-friendly GK107 did see a simultaneous launch, but in mobile-only form as the 640M.

Given the configuration of GK107, it appeared likely that a desktop version would tick off all the boxes necessary for a HTPC. Does the Zotac GT 640 fulfill our expectations? The short answer is: Yes, it does! It improves upon the performance of the GT 430 with respect to madVR, thanks to the extra computational power and memory bandwidth. Meanwhile the updates to the video outputs (HDMI PHYs) and the retention of the VPU from the GT 520 enable decode and display of 4K videos in their native resolution.

However, these updates don't mean that NVIDIA's GPUs are perfect for HTPCs. Just like every other HTPC GPU vendor out there, NVIDIA has a list of things which need to be fixed from a HTPC perspective, which we'll dive into in a moment.

Another important update present in the Kepler series is the on-board H.264 encoder. The practice of integrating a H.264 encoder in the GPU was started by Intel in Sandy Bridge. While Intel has the second generation version of QuickSync in the Ivy Bridge processors, AMD and NVIDIA are just now starting to ship their first generation encoders (VCE and NVENC respectively).

Both VCE and NVENC are yet to gain widespread support amongst the software vendors, and NVIDIA themselves indicated that full support for NVENC in CyberLink's and ArcSoft's offerings would be coming sometime next month. Keeping this in mind, we have decided to postpone NVENC coverage to a later date.

In the next few sections, we will look at the HTPC aspects of the Zotac GT 640. Before delving further into that, the details of our testbed are provided below:

Note that we used three different HDMI sinks for our testing. While the fancy Sony VPL-VW 1000ES was used to test out 4K resolution output, the Sony KDL46EX720 + Pioneer VSX-32 was used to verify HD audio bitstreaming. The rest of the tests (including HQV benchmarking) were performed with the Acer H243H monitor.