HD 7950 Launched: GTX 580 Gets a Pasting

Yesterday, AMD launched the Radeon HD 7950 3GB graphics card, the little brother of the HD 7970 3GB. Judging by the reviews and the price, it will give its primary competition, the NVIDIA GTX 580 a pasting.

The basic reasons for this are:

• Slightly faster than the GTX 580 in most real-world gaming benchmarks
  
• Launch price £340 - £400. The cheapest being right in the ballpark of the cheapest GTX 580s and perhaps slightly lower. This makes it excellent value for money
  
• Performance only slightly less than its big brother
  
• 28nm technology versus the older 40nm technology that the GTX 580 is based on
  
• Overclocks like a banshee!

With stats like these, NVIDIA's current best single-GPU card has clearly met its match in terms of price and performance, which is arguably bad news for NVIDIA, which might see its sales crater. While the HD 7970 of course beats the GTX 580 by a wider margin, it's significantly more expensive, allowing the buyer to trade price for performance. This card lets you have your cake and eat it too.

I can see a potential price war looming, giving PC gaming enthusiasts high-powered graphics cards at cheaper prices, which is great and really something to look forward to.

Now, let's get to the technical aspects of this new card. What does it look like? Just like the HD 7970 - except for the little sticker on the back in tiny hard-to-read text that identifies it as a HD 7950. It has all the same connectivity options too, namely a DVI port, one full size HDMI port and two mini-DisplayPorts and a two-finger CrossFire connector for three or four cards in CrossFire.

As can be expected, the differences come down to the cut-down 28nm "Tahiti" GPU, but what's interesting, is that the only other  cuts made are to the power circuitry, which has one less VRM phase and two 6-pin PCI-E power connectors, rather than the 8+6 connectors on the HD 7970. Everything else about the card stays the same, including the memory bus, which remains at 384-bit. Note that the clock speeds are reduced too, GPU down from 925MHz to 800MHz and the memory from 1375MHz to 1250MHz.



As can be seen from the GPU diagram above, the HD 7950 has four Graphics CoreNext (GCN) Compute Units disabled, bringing them down from 32 to 28. And that's it. Of course, this begs the question of whether they will be unlockable to a full HD 7970 by flashing the BIOS like on previous generation AMD cards. Only time will tell, but it must be kept in mind that the GPU may be held back by its weaker, cut-down power supply. As this is an expensive, high end card, any enthusiasts may well choose to avoid risking it, even though it comes with a dual BIOS. This GPU has the same number of transistors as its big brother, at 4310M and the same number of ROPs, at 32.

This card overclocks to similar ceiling frequencies as the HD 7970, so the results are even more stellar, coming in at a whopping 30% or so real-world improvement, which is fantastic when you think about it.

The one thing that isn't so hot about this card is its cooler: it's noisy. This is the same noisy turbine that was introduced with the HD 2900 way back in May 2007 and can definitely make an annoying amount of noise. The GTX 580s cooler on the other hand, is very well behaved and not as disconcertingly loud as this one. This is especially odd, as this effectively underclocked card consumes less power than the already frugal HD 7970 and therefore puts out less heat. Note that it's also the noise quality that can be bothersome, rather than just the volume. So, if NVIDIA can have a reasonably quiet cooler with a GPU that consumes almost twice the power, why can't AMD make this one reasonably quiet? Should be a piece of cake, no?

Of course, it can be assumed that NVIDIA won't take this lying down, so we await their answer, which is likely to show up sooner rather than later. There's been rumours of the next-gen Kepler GK104-based card coming out soon, which might see off the HD 7950. Note that the GK104 isn't the top-end GPU, that would be the GK100, which comes somewhat later. Even without this card though, the GTX 580 is a decent overclocker, so it's quite possible that significantly overclocked versions with a tweaked GPU (improved stepping?) and 3GB RAM may be released soon at aggressive prices. A little patience will reveal NVIDIA's strategy soon enough.

Source: TechPowerUp reviewwhich also has benchmarks for the HD 7970 for comparison.