After some heavy price reductions the GeForce 8600 GTS has now reached a point where it makes sense to recommend it. But of course, there is a new player in town now, the Radeon HD 2600XT carries a MSRP (Manufacturer's Suggested Retail Price) of just $150 and specifications to match the GeForce 8600 GTS.

The Radeon HD 2600XT pricing does vary depending on the brand and specifications, as there are a number of variations of this product. While the majority of GeForce 8600 GTS graphics cards come loaded with 256MB GDDR3 memory, there are as many 256MB Radeon HD 2600XT cards as there are 512MB versions. We have found that the Radeon HD 2600XT can come fitted with GDDR4 memory as well as GDDR3 memory, which translates in prices ranging from as low as $100 and up to $170. The more expensive cards all seem to be factory overclocked and generally come with 512MB of on-board memory.

Today we will be comparing these two mid-range graphics cards head to head using a 512MB VisionTek Radeon HD 2600XT and a 256MB ASUS GeForce 8600 GTS. While neither product features overclocking out of the box, the Radeon has an obvious advantage in that it sports twice as much video memory. And while this may appear to be unfair, we have found that the average 512MB Radeon HD 2600XT graphics card retails for just $140, while the average price of a GeForce 8600 GTS sporting 256MB of memory is $160. That said, 512MB versions of the GeForce 8600 GTS are priced at over $200.

How the cards match up?

Since these two graphics cards are based on a similar architecture to that of their flagship parts, we can anticipate they are quite different in design.

The Radeon HD 2600XT is built around ATI's RV630 architecture, while the GeForce 8600 GTS is based on the Nvidia G84 design. Both are built predominantly for use with the PCI Express x16 bus, though the Radeon HD 2600XT also supports the older AGP interface - Nvidia just recently expressed interest in releasing the GeForce 8 series for those still using AGP through the use of a bridge chip.

Officially the GeForce 8600 GTS is designed to only support 256MB of on-board memory, but that has not stopped a few select manufacturers from doubling that number. At this point we do not believe the extra 256MB really helps the performance of the GeForce 8600 GTS and for the price premium the GeForce 8800 GTS (320MB) would become a much smarter option. The Radeon HD 2600XT can come with either 256MB or 512MB of memory and there is no real serious price premium if you go for the latter.

Let’s talk core and memory speeds as this really is where the two begin to show their differences. The GeForce 8600 GTS comes clocked at 675MHz with a memory frequency of 2000MHz. This allows for a theoretical memory bandwidth of 32.0GB/s which is still impressive for a mid-range contender (compare that to the GeForce 8800 Ultra's 103.7GB/s).

The Radeon HD 2600XT on the other hand comes clocked at a staggering 800MHz, while the memory frequency does vary from 1400MHz to an amazing 2200MHz, depending on the memory used. The GDDR4 versions of the Radeon, which cost significantly more, come with the 2.2GHz memory, while the GDDR3 versions like the one we are testing today generally come clocked at 1.4GHz.

The Radeon HD 2600XT features 120 SPs (Stream Processors) which is considerably less than the 320 found on the higher-end and more expensive Radeon HD 2900XT. There are just 8 TMUs (Texture Mapping Units), half that of the 2900XT and 4 ROPs (Raster Operation Pipelines).

This still makes the Radeon HD 2600XT look somewhat more powerful than the GeForce 8600 GTS on paper. The GeForce 8600 GTS only features 32 SPs - though they are clocked at 1180MHz whereas the 24 shader processors (120 stream processors) of the Radeon HD 2600XT are clocked at 800MHz. The GeForce 8600 GTS has an advantage when it comes to its texturing capabilities with twice as many TMUs built in this GPU.

The GeForce 8600 GTS also has a serious advantage when it comes to pixel outputting as it features twice as many ROPs. The 8600 GTS boasts two ROP partitions that can output four pixels per clock, while the Radeon HD 2600XT has just the one supporting four pixel pipes. The Radeon HD 2600XT runs its ROPs at 800MHz for a 3200 Mpixels/sec fillrate, while the GeForce 8600 GTS comes out on top working its ROPs at just 540MHz for a 4320 Mpixels/sec fillrate.

In terms of raw computing power the Radeon HD 2600XT can achieve 192 GigaFLOPS, while the GeForce 8600 GTS can produce just 113.3. When talking about Z-only processing however, the GeForce 8600 GTS is far superior as it can perform 32 pixels per clock while the Radeon can only do 8.

With so many differences to talk about, this battle cannot be played out on paper, therefore we must now turn to real-life tests to determine which of these two products comes on top and deserves the recognition as the best mainstream graphics solution currently available.

Conclusion, an unusual one

Despite featuring twice as much video memory, the HD 2600XT was unable to match the 8600 GTS on more than one occasion. Truth be told, these mid-range performance products are not nearly as fast as we expected them to be, though this has been known for quite some time now. The GeForce 8600 GTS is roughly as fast as the previous generation 7900 GS, depending on the game used for testing.

If we were presented with a 7900 GS and a 8600 GTS, and then told to pick one, we would most likely grab the 7900 GS every time. Given there is very little price difference between the two, we imagine most of you would do the same.
A similar scenario is presented with the Radeon HD 2600XT, which is also much slower than we had hoped for. Given that the 512MB version we used today does cost roughly the same amount as a Radeon X1950 Pro, we would also pick the latter over this new DX10 mid-range solution.

This is an interesting situation and not one we have ever encountered before. Almost a year ago we compared the GeForce 7900 GS and the Radeon X1950 Pro head to head to determine which would be the better buy. Back then we recommended the Radeon X1950 Pro over the GeForce, despite of the fact it cost considerably more. The Radeon X1950 Pro was an impressive performer and not only for its time, today we are still finding this graphics card to be an exceptional performer.

Just recently we published a Bioshock videocard performance article which showed the Radeon X1950 Pro polishing off the very two (new generation) graphics cards tested today. So given a $150 budget, we would still pick the Radeon X1950 Pro over all current offerings. From a gamer's point of view the only thing the X1950 Pro lacks is DirectX 10 support, which in my opinion works to be the same if we had it or not on the Radeon HD 2600XT and GeForce 8600 GTS anyway.

The whole point of DX10 is to improve visual quality, and so far we have seen almost no games taking full advantage of this new rendering technology.

Elaborating further on this subject, the problem becomes that these mid-range graphics cards are too slow to play DX10 games. Sure, you can use the GeForce 8600 GTS to play Bioshock in DX10 mode, but in order to achieve playable performance, the visual settings must be shut down a notch and things like shadows that actually look a bit better in DX10, must be turned off.

In other words, because the older Radeon X1950 Pro is actually faster, it can deliver more playable rates using higher quality visual settings and therefore will look better in DX9 when compared to a GeForce 8600 GTS running in DX10.

Arguably as more titles are released to take advantage of DirectX 10, this scenario might change. But then if you think that DX10 is Vista exclusive, and any game developer on its right mind will release games that are backward compatible with Windows XP at least for the next 18 months, there is a narrower possibility of regretting our decision.

Therefore, in our comparison between the Radeon HD 2600XT and the GeForce 8600 GTS, we have found the Radeon X1950 Pro to be the winner, go figure.

Thanks go to Visiontek for sending us the Radeon HD 2600XT board we tested today. They make good products including Radeon X1950 Pro boards in both PCIe and AGP flavors, so check them out.