Kalniel's guide to enthusiast ATI cards

[kalniel]

There's been a recent trend among graphics card manufacturers for getting the most out of each grade of silicon quality - rather than just lump the best performing chips in high end cards and the rest in low end, both nVidia and ATI have been introducing a range of SKUs that cater for performance across a wide range of prices.

I have to applaud nVidia's naming scheme at the moment - it's relatively clear what the chips are and which is better than which. However, ATI seem to have created a bit of a mess, which is what this guide aims to clear up a bit.

It's mostly for my own benefit, so please chip in with corrections etc. Note models in italics are speculation

R580 based products

The R580 chip is a refresh of the R520 chip, firmly fixing any problems. ATI have also uncoupled the pixel shaders compared to R520 products, giving 3 shaders per pipeline instead of 1. 90nm.

• X1950XTX - The current top range card. This is a refresh of the 1900XTX product, introducing GDDR4 memory and a better cooler design. GPU: 650mhz, Gmem: 512mb GDDR4 1000mhz, Pipes: 16tex|48pshader|16z|8vshader
• X1900XTX - The top binned 1900 product. GPU: 650mhz, Gmem: 512mb GDDR3 775mhz, Pipes: 16|48|16|8
• X1900XT - GPU: 625mhz, Gmem: 512mb GDDR3 725mhz, Pipes: 16|48|16|8
• X1900XT - 256mb version of the X1900XT. This enabled the price to drop into the competative upper mainstream market. GPU: 625mhz, Gmem: 256mb GDDR3 725mhz, Pipes: 16|48|16|8
• X1950XT - New card, rather than just drop clocks, ATI have disabled a quad of pipelines. A more consistent name would be 1950GT. Good bump on GDDR3 mem though GPU: ~625mhz, Gmem: 256mb GDDR3 ~800mhz, Pipes: 12|36|12|8
• X1900GT - rev 1 - This is a 1900XT with one quad of pipelines disabled and reduced clocks. GPU: 575mhz, Gmem: 256mb GDDR3 600mhz, Pipes: 12|36|12|8
• X1900GT - rev 2 - Annoyingly, ATI have just changed specification on the 1900gt, possibly an attempt to make newer cards look better, or to make use of stock parts. Processor speed is down, memory speed is up. GPU: 512mhz, Gmem: 256mb GDDR3 700mhz, Pipes: 12|36|12|8

R570 based products

The latest chip from ATI, this is their first 80nm chip. It runs cooler and uses less power than previous chips.

• X1950pro - Replacement for the 1900GT, this low power/heat card is built to spec (no disabled pipelines). Uses an internal bridge for crossfire rather than external cable.GPU: 580mhz, Gmem: 512mb GDDR3 700mhz, Pipes: 12|36|12|8
• X1950pro - 256mb version of the above. GPU: 580mhz, Gmem: 256mb GDDR3 700mhz, Pipes: 12|36|12|8

R520 based products

ATI are glad to see the back of this chip - a small design flaw held up the release of this chip for months. One of the features this chipset introduces is the 512bit ring bus memory controller - while this still communicates to the outside world through a conventional 256bit bus, it reduces internal latency, and importantly for ATI, allows flexibility in choice of memory. Has a 1|1|1 textures|pixelshaders|Z ratio. 90nm.

• X1800XT - The 'fixed' core. GPU: 625mhz, Gmem: 512mb GDDR3 750mhz, Pipes: 16|16|16|8
• X1800XT - 256mb version to drop the price. GPU: 625mhz, Gmem: 256mb GDDR3 750mhz, Pipes: 16|16|16|8
• X1800XL - ATI had to do something with all the chips produced with the design flaw, the XL is the result. GPU: 500mhz, Gmem: 256mb GDDR3 490mhz, Pipes: 16|16|16|8
• X1800GTO - A use for chips that didn't make the quality cut for the XL or XT, this has a quad of pipelines disabled. GPU: 500mhz, Gmem: 256mb GDDR3 490mhz, Pipes: 12|12|12|8

[BrynS]

Nice list, kalniel.

One query though, what's your source for the X1950XT having one quad disabled? As far as I can recall, the only qualifier mentioned recently was that it would be equipped with 256MB RAM only (as GDDR4 is still pricey) versus the 512MB on X1950XTX and priced to compete with the 7950GT. I don't recall any mention of clocks either.

Cheers,

BrynS

[kalniel]

It's speculation, based on the thought that without a disabled quad it would out-compete the X1900XT 256 whilst being at least 20 quid cheaper. Reference clock info I've heard rumour of is 625/900, but I believe vendors will push this to ~650/~1000.