TechRadar Verdict
On paper, this is a real winner, but in practice the GT remains the real weapon of choice
Pros
- +
High speed version of the G92 core
- +
Full complement of 128 stream procs
Cons
- -
Relatively narrow memory bus
- -
No faster than an overclocked GT
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The graphics world isn't exactly known for its straightforward nomenclature. With so many suffixes per chip - your GTs, GTXs, Pros, XTs and so on - it's no surprise that punters are often confused about what's what. Two seemingly innocuous letters can separate cards that have absolutely nothing in common performance-wise beyond an ability to make pretty colours appear on your screen. Does NVIDIA's decision to release a third card carrying the 8800GTS name make life easier or more difficult? It's hard to say...
In the wild
You'll spot this latest version of the card because it nominally carries 512MB of memory on board - not unlike the 8800GT, which was recently released to general acclaim and has ensured 'NVIDIA' will be the most popular boys' name for children born this year. Inside its silicon heart there are yet more similarities with the GT: it's based, for example, on the G92 core.
In brief, G92 is a refined version of G80, designed on a 65nm process with a more polished instruction issue engine and capable of much higher clockspeeds. It also features the Pure Video 2 engine for improved HD decoding.
To earn its extra consonant, the 8800GTS has the full complement of 128 stream processors previously seen in the 8800GTX and Ultra cards, and thanks to the difference in G92 architecture, it has double the number of texture address units that those cards boasted. On paper then, it's a superior card in every manner - from clock speeds to shader counts - to every previous NVIDIA chip.
Almost, anyway
Actually, we lied a little there. There is one small detail in which the previous 8800GTS, the GTX and the Ultra all have the upper hand, and that's in the number of ROPS (render output units) and, as a result, the memory bandwidth available. The Ultra and GTX both boast 384-bit interfaces, the previous GTS 320-bits and yet the new GTS 512 has the same four 64-bit controllers as the GT, yielding a total bus between the graphics core and the frame buffer of just 256-bits.
The question is, does it make a difference to performance?
NVIDIA says no
At first glance, the fact that all the clock speeds, including the memory, are higher on the G92-based cards, than their G80 counterparts should offset some of this bandwidth deficit. And they do: despite having a full 50 per cent extra width, the difference in theoretical maximum data transfer rates, between a GTX and a GTS 512 is only about 40 per cent.
But then there's the improved compression algorithms, which are being used to ship data across the memory bus: that should help these cards keep up, shouldn't it?
The narrower bus means many things for NVIDIA - for a start, it keeps production costs down, hence the relatively cheap nature of the new releases. It also means that there's probably another, even faster card coming in the new year with the missing ROPS enabled.
The sad fact is that while the 8800GTS is faster than the GT, it's not fast enough to justify the price premium. In fact, it's in exactly the same ballpark as the overclocked versions of the GT, which are around £40 cheaper, which makes us fairly certain that the extra shader power is being held back by the lack of memory bandwidth. What it all boils down to is that if you can't play Crysis at a certain resolution with Ultra High settings on a GT, you aren't going to be able to do it on a GTS either.
Indeed, the performance deltas between the GT, the new GTS and even the Ultra are all so narrow now, that if anyone is buying a new card it's a no brainer to go for the cheapest and wait to grab a high-end card from the next generation - which is due early next year. If you're feeling flush in the January sales bear this in mind: two GTs in SLI mode aren't that much more expensive than a single GTX.
But wait...
There is, however, one thing left in the GTS' favour. At stock speeds, it's competitive with a GT overclocked to 700MHz core. The larger heatsink on the GTS gives it a lot more overclocking headroom, and it's a stabler card all round in the high resolution tests we ran beyond stock speeds. At 700/1,000MHz core and memory, for example, it really did start to pull away from GT, and Asus has a factory overclocked TOP version, which starts at 740MHz and is apparently overclockable from there. While the GTS isn't the card we'd recommend to most, anyone who's prepared to get their hands dirty and possibly invest in a water cooler system could easily get this core up to the performance of the Ultra card.
