AMD ATI Radeon HD 2600 XT, 2600 Pro and 2400 XT Review
The 2600 XT
In mid-May AMD announced the entirety of a new lineup of graphics cards based on the R600 architecture. At the time though, only the flagship ATI Radeon HD 2900 XT card was made available to compete with the top cards from NVIDIA's 8-series of GPUs. We shared most of the technical information on the remainder of the Radeon HD 2xxx series then, but what we couldn't tell you about yet was the performance. After a six week wait, we can finally do so.
The cards that we are reviewing here today are mid-range to budget priced video cards; prices top out at the $150 range for the Radeon HD 2600 XT. This does leave a conspicuous gap between the 2600 XT and the 2900 XT, but we'll touch on that later on down the road. For now, let's take a look at each of the cards on the chopping block today.
For some background on the architecture and technology behind the AMD Radeon HD 2xxx series of graphics cards, you'll definitely want to check out my original review of the HD 2900 XT from May. It has all same block diagrams you'll see below for the flagship cards as well as more detail on the stream processors, texture units, memory controller and more. You might consider it a pre-req for this article.
The AMD ATI Radeon HD 2600 XT
This could be considered the "flagship" of AMD's mid-range graphics cards as it has the highest price and fastest gaming performance of the new AMD cards introduced today. The architecture of the Radeon HD 2600 XT is much like that of the 2900 XT, though with fewer stream processors, etc.
Radeon HD 2600 architecture
Here is the 2600 GPU in its block diagram glory. While the flagship 2900 XT architecture features 320 stream processors, 16 texture units and 16 ROPs, the 2600 architecture (for both 2600 XT and the 2600 Pro) is powered by 120 stream processors, 8 texture units and 4 ROPs. As you might guess, that gives the 2600 series considerably less horsepower though at a lower price and lower power consumption.
These tables offer us a quick glimpse at some of the main differences in the GPUs from AMD's Radeon HD 2xxx series. Anything that shows a range (like 400-800 MHz) simply means that different cards in that series will have different speeds. Another big performance difference between the HD 2900 XT and the HD2600 cards is the memory interface: it's only 128-bits on the mid-range cards versus 512-bits on the flagship. That will be another big performance hit for these cards.
The AMD ATI Radeon HD 2600 XT card is seen here with a single slot cooling design and bright red PCB. The official specs of this card from AMD are:
Radeon HD 2600 XT
120 stream processors, 8 texture units, 4 ROPs
800 MHz clock speed
256MB frame buffer
128-bit memory interface
1100 MHz GDDR4 memory clock
65nm (G+) process technology
The 65nm process that AMD is using on the 2600 cards is what allows it to reach a higher clock speed than the 2900 (which ran at 740 MHz) while maintaining a much lower power consumption rate.
The fan on this design is actually VERY quiet, more so than on any other AMD/ATI card I have seen in recent years. Even the Radeon HD 2400 fan seems loud in comparison.
The same internal, native CrossFire design that was in place for the X1950 Pro cards last year continues on with the 2600 XT cards.
The outputs on the Radeon HD 2600 XT include two dual-link DVI and an HDTV output with included dongle.
The 2600 XT also supports and comes with the DVI-to-HDMI adaptor (shown here attached to the 2900 XT) that can also output digital audio thanks to the on-die audio codec. See this page of our HD 2900 XT review for all the details on that feature.
At 390 million transistors, the HD 2600 XT is a small chip when compared to its 700 million transistor older brother and the G80's 681 million transistors.