Board analysis

Reference board design

Like previous high-end launches (such as the GeForce 6800 Ultra last year), NVIDIA is keeping tight control over their board partners for GeForce 7800 GTX. Right now NVIDIA is handling all 7800 GTX board production; NVIDIA’s board partners merely purchase the completed cards from NVIDIA, slap their sticker on the card’s fan, and bundle the card with their promotional material and packaging. This is pretty much as close to purchasing the board directly from NVIDIA as it gets.

Other than the sticker on the cooler, the 7800 GTX reference board (bottom) looks the same as EVGA card

Top of the EVGA card

The back of the card

By handling all the early production themselves, this allows NVIDIA to ensure that a certain minimum level of board quality is met. In the past, some board partners have skimped on some board components in order to reduce manufacturing costs. Another added benefit for NVIDIA is that supply can be tightly controlled, as they’re manufacturing the cards themselves rather than their board partners. This helps NVIDIA and their board partners bring their products to market quicker, and likely played a key role in the 7800 GTX’s successful availability so soon after the GPU’s official launch.

EVGA makes one key modification to NVIDIA’s reference specs however: for their e-GeForce 7800 GTX card, they’ve decided to clock the graphics core 20MHz higher than default, up to 450MHz when running in 3D mode (the e-GeForce 7800 GTX still runs at 275MHz in 2D mode). Graphics memory speed remains unchanged, at 600MHz, as that’s the speed that the board’s 1.6ns Samsung memory modules are officially rated for. FYI, these are the same memory modules used for GeForce 6800 Ultra a year ago.

EVGA provides two different SKUs for the GeForce 7800 GTX. A limited edition SKU which includes a copy of EA/DICE’s popular online shooter, Battlefield 2 on DVD-ROM, the e-GeForce 7800 GTX Battlefield 2 Edition (Part Number 256-P2-N538-AX), and a second SKU which doesn’t, the e-GeForce 7800 GTX (Part Number 256-P2-N528-AX). The Battlefield 2 SKU retails for a little bit more than the vanilla 7800 GTX card, carrying an MSRP of $619.99 versus $599.99, but well worth it when you factor in the cost of Battlefield 2, which sells for $49.99 at most stores. EVGA also produces a third SKU (Part number 256-P2-N525-AX) that ships at stock clock speeds.

We received the vanilla e-GeForce 7800 GTX SKU for our testing.

Extra cooling here and PCI-E power connector

VIVO box with component outputs

Back of the VIVO box

Also included in the card’s packaging is a VIVO box with integrated component outputs for hooking the e-GeForce 7800 GTX up to an HDTV, two DVI adapters, a PCI-E power adapter, and an S-Video cable. EVGA also includes a small manual and two case stickers inside the box. Finally, software included with the e-GeForce 7800 GTX is a copy of CyberLink’s PowerDirector 2.55.

Overclocking

As Guru3D discovered earlier this month, the GeForce 7800 GTX’s clocks are slightly more complicated than originally thought. Apparently NVIDIA clocks certain parts of the graphics core at different clock speeds. It appears that the graphics core and pixel clocks are the same (450MHz for the EVGA card, 430MHz for reference 7800 GTX boards), but the geometry clock runs approximately 40MHz higher, 490MHz in the case of our EVGA card. This would be similar to the techniques AMD and Intel use in their latest processors, where different parts of the processor run at frequencies higher than the core clock speed (remember Intel’s “double-pumped” integer ALUs from the original P4 launch?).

Note the 529MHz clock speed indication, 40MHz higher than our OC

It’s unclear which portion(s) of the chip “geometry clock” refers to, the most natural example you may assume would be the vertex units. With only 8 units, it’s possible that NVIDIA can clock these a little higher than the pixel shading engine without affecting yields too badly, or “geometry clock” could refer to an entirely different portion of the graphics core. If NVIDIA were to provide more information on the 7800 GTX’s clocks, overclockers could really go to town tweaking their card’s performance. Could you imagine being able to adjust three or four different clocks in your 7800 GTX card? In applications where you’re more vertex-bound, you could bump up the vertex engine’s clock more, or perhaps you could overclock your pixel shaders just a little bit more for added performance.

One last thing we should note, this 40MHz clock speed bump still applies if you manually overclock your graphics card. For instance, we were able to overclock our e-GeForce 7800 GTX up to 489MHz on the core, as a result, RivaTuner monitored the card running at 529MHz.