Faster Graphics For Lower Prices: ATI Radeon HD 4770

Meet The Radeon 4770

With 826 Million transistors, the RV740 GPU that powers the Radeon HD 4770 features a native 640 SP (128 five-wide vector units arranged in 8 SIMD cores) as opposed to the 640 cut-down-from-800 SP 4830. Among the other differences is the fact that the 4770 hooks into GDDR5 over a 128-bit memory bus at almost the same clock speed (producing just a little bit less bandwidth at half the pinout).

AMD reports average TDP to be about 80W, so despite the fact that this is a 40nm part that pulls a little less power for the same job than its older brothers, the Radeon HD 4770 still requires a 6-pin PCIe power connector. This isn't a huge amount of power, and AMD has single slot boards that fall in to this range. Of course, it likely gets a little more complicated at 40nm when you have less surface area to dedicate to heat transfer. Thus this is a dual slot part rather than a single slot part. Such is life.

So, rather than a totally killer single slot card with no power connector at $99, we've got a dual slot card with a power connector at $110. Not ideal, but we can work with that. Rather than the 40nm process, form factor or targeted design being the selling point, the real issue is going to be the competition.

We will be comparing the Radeon HD 4770 to the GeForce GTS 250 512MB (aka the 9800 GTX+) and the GeForce 9800 GT. These two cards sort of sandwich the Radeon HD 4770 in terms of price with the 9800 GT coming in at $100 and the GTS 250 512MB at slightly more than $120. So the question will continually be: does the extra +/- $10 make a difference.

This part essentially improves upon and usurps the position of the Radeon HD 4830. Word from AMD was that we should see the 4830 start to fall by the wayside. For our analysis we are including the Radeon HD 4830 and the Radeon HD 4850. Here's a breakdown of how the AMD hardware stacks up:

It's worth noting that the bandwidths of the 4770 and the 4830 are 51.2GB/s and 57.6GB/s respectively.

We have also tweaked a couple of our tests to better target the ~$100 segment. The biggest change was with our Crysis test where we dropped everything down by one quality level ending up with all mainstream settings except for gamer shaders. The other was just a small tweak: not pushing things beyond the high quality default settings in Age of Conan (though we did enable 4xAA).

In the middle of testing, we accidentally let our copy of Left 4 Dead update itself rendering our benchmark un-timedemo-able. Thus we have to leave Left 4 Dead performance out of this article, but we can say that at the highest quality settings the 4770 is capable of playable framerates at up to 1680x1050.

Our test setup is still the Intel platform with a top of the line CPU in order to remove any other bottlenecks from the system. These performance numbers show the potential the graphics card has to offer. If the rest of a system is unable to achieve performance levels along the lines of what we show here, then it doesn't matter what graphics card we plug in at this price: it will end up performing pretty much the same as any other option (at the system bottleneck level). These tests show the potential of a graphics card when the potential of the graphics card makes a difference. That said, most Phenom II, Core 2, and Core i7 systems will be very close to these numbers at the common resolution of 1680x1050 with the tested hardware; the fast system/CPU generally only becomes a factor at lower resolutions or with multiple GPUs.

Without further ado, here's the performance numbers.