Components

Saturday, May 26, 2007

Nvidia GeForce 8800 Ultra

WHAT HAPPENS WHEN YOU take the fastest video card on the planet and turn up its clock speeds a bit? You have a new fastest video card on the planet, of course, which is a little bit faster than the old fastest video card on the planet. That's what Nvidia has done with its former king-of-the-hill product, the GeForce 8800 GTX, in order to create the new hotness it's announcing today, the GeForce 8800 Ultra.

There's more to it than that, of course. These are highly sophisticated graphics products we're talking about here. There's a new cooler involved. Oh, and a new silicon revision, for you propellerheads who must know these things. And most formidable of all may be the new price tag. But I'm getting ahead of myself.

Perhaps the most salient point is that Nvidia has found a way to squeeze even more performance out of its G80 GPU, and in keeping with a time-honored tradition, the company has introduced a new top-end graphics card just as its rival, the former ATI now owned by AMD, prepares to launch its own DirectX 10-capable GPU lineup. Wonder what the new Radeon will have to contend with when it arrives? Let's have a look.

By and large, the GeForce 8800 Ultra is the same basic product as the GeForce 8800 GTX that's ruled the top end of the video card market since last November. It has the same 128 stream processors, the same 384-bit path to 768MB of GDDR3 memory, and rides on the same 10.5" board as the GTX. There are still two dual-link DVI ports, two SLI connectors up top, and two six-pin PCIe auxiliary power connectors onboard. The feature set is essentially identical, and no, none of the new HD video processing mojo introduced with the GeForce 8600 series has made its way into the Ultra.

Yet the Ultra is distinct for several reasons. First and foremost, Nvidia says the Ultra packs a new revision of G80 silicon that allows for higher clock speeds in a similar form factor and power envelope. In fact, Nvidia says the 8800 Ultra has slightly lower peak power consumption than the GTX, despite having a core clock of 612MHz, a stream processor clock of 1.5GHz, and a memory clock of 1080MHz (effectively 2160MHz since it uses GDDR3 memory). That's up from a 575MHz core, 1.35GHz SPs, and 900MHz memory in the 8800 GTX.

The Ultra's tweaked clock speeds do deliver considerably more computing power than the GTX, at least in theory. Memory bandwidth is up from 86.4GB/s to a stunning 103.7GB/s. Peak shader power, if you just count programmable shader ops, is up from 518.4 to 576 GLOPS—or from 345.6 to 384 GFLOPS, if you don't count the MUL instruction that the G80's SPs can co-issue in certain circumstances. The trouble is that "overclocked in the box" versions of the 8800 GTX are available now with very similar specifications. Take the king of all X's, the XFX GeForce 8800 GTX XXX Edition. This card has a 630MHz core clock, 1.46GHz shader clock, and 1GHz memory.

So the Ultra is—and this is very technical—what we in the business like to call a lousy value. Flagship products like these rarely offer stellar value propositions, but those revved-up GTX cards are just too close for comfort.

The saving grace for this product, if there is one, may come in the form of hot-clocked variants of the Ultra itself. Nvidia says the Ultra simply establishes a new product baseline, from which board vendors may improvise upward. In fact, XFX told us that they have plans for three versions of the 8800 Ultra, two of which will run at higher clock speeds. Unfortunately, we haven't yet been able to get likely clock speeds or prices from any of the board vendors we asked, so we don't yet know what sort of increases they'll be offering. We'll have to watch and see what they deliver.

We do have a little bit of time yet on that front, by the way, because 8800 Ultra cards aren't expected to hit online store shelves until May 15 or so. I expect some board vendors haven't yet determined what clock speeds they will offer.

In order to size up the Ultra, we've compared it against a trio of graphics solutions in roughly the same price neighborhood. There's the GeForce 8800 GTX, of course, and we've included one at stock clock speeds. For about the same price as an Ultra, you could also buy a pair of GeForce 8800 GTS 640MB graphics cards and run them in SLI, so we've included them. Finally, we have a Radeon X1950 XTX CrossFire pair, which is presently AMD's fastest graphics solution.

I also prefer the Ultra to the option of running two GeForce 8800 GTS cards in SLI, for a variety of reasons. The 8800 GTS SLI config we tested was faster than the Ultra in some cases, but it was slower in others. Two cards take up more space, draw more power, and generate more heat, but that's not the worst of it. SLI's ability to work with the game of the moment has always been contingent on driver updates and user profiles, which is in itself a disadvantage, but SLI support has taken a serious hit in the transition to Windows Vista. We found that SLI didn't scale well in either Half-Life 2: Episode One or Supreme Commander, and these aren't minor game titles. I was also surprised to have to reboot in order to switch into SLI mode, since Nvidia fixed that issue in its Windows XP drivers long ago. Obviously, Nvidia has higher priorities right now on the Vista driver front, but that's just the problem. SLI likely won't get proper attention until Nvidia addresses its other deficits compared to AMD's Catalyst drivers for Vista, including an incomplete control panel UI, weak overclocking tools, and some general functionality issues like the Oblivion AA problem we encountered.

That fact tarnishes the performance crown this card wears, in my view. I expect the Ultra to make more sense as a flagship product once we see—if we see—"overclocked in the box" versions offering some nice clock speed boosts above the stock specs. GeForce 8800 Ultra cards may never be killer values, but at least then they might justifiably command their price premiums.

We'll be keeping an eye on this issue and hope to test some faster-clocked Ultras soon.