Grrr!

The Xbox 360 has 16 TMUs, 8 ROPs (tied to the eDRAM which is quad pumped), and 48 Shader ALUs in a 3 way array.

The G70, the appearant heir to the RSX, has 24 TMUs, 24 Fragment Pixel Shader units, and 16 ROPs. TOTALLY different designs. Further, the G70 Fragment shaders have 2 ALUs and each has a mini-ALU.

So you COULD say that the RSX has 48 Shader ALUs + 48 mini-ALUs!

But it don't necessarily work like that. Effeciency is a big issue. e.g. the mini-ALUs are not always used. And of course in a "traditional" DX9 design you run into a couple of issues:

1: PS:VS balance of the game. Some games are more VS heavy than others. This means certain games "waste" processing resources.

2: PS:VS balance changes scene to scene. Are you looking at a single big wall with a large normal map? That is a PS heavy scene and the VS shaders are wasted. Are you overlooking a valley with tons of trees with individual leaves? This is VS heavy.

3: PS:VS balance in the rendering pipeline shifts. Are you working on stencile shadows? Then you will spend a couple clocks doing nothing but VS work.

RSX and Xenos approach issues differently. RSX is a brute force design whereas Xenos is a more elegent design aimed at using all of the prcoessing resources as often as possible. On paper Xenos has an edge in many ways architecturally and is more effecient BUT RSX is no wimp AND it has a lot of power in there. You CANNOT just compare "pipelines" because NEITHER GPU HAS PIPELINES.Chicken-or-Egg. Do games use more PS because the GPUs have more PS power? Is it because in the past there were memory constraints and a move toward Normal Maps?

We cannot expect PS:VS balance to remain the same forever. Further, many advanced effects are VS heavy.Errr no. The R580 has 48 Pixel Shading ALUs @ 650MHz + VS.

Xenos has more features (eDRAM, FP10 blending, hardware tesselation, MEMEXPORT) and all of its VS have a texture lookup (meaning displacement mapping can be realistically used) BUT from a pure performance perspective the R580 has more brute force. It has just as many PS ALUs at a 30% faster clock and they will ALWAYS be used for PS. The Xbox 360 Shader ALUs have to do VS and PS work.

The 360 has some advantages (e.g. ROPs ties to the eDRAM for very cheap AA, more features) but if I had to choose I would take the R580. It has been said the R580 can beat the 7800GTX in SLI in some situations. Which is not surprising because the X1800XT with the newest drivers does very well in some modern games (FEAR, CoD2) compared to the 7800GTX. Heck, at 1600x1200 4xA 16xAF the X1800XT--with 16 fragment PS--beats the 7800GTX 512MB in BF2, FEAR, and ties in CoD2.

In some ways that does give us a peak at the 360 and RSX--but only slightly as the CPUs and Memory configurations make a difference. Obviously these tests don't tell us much about the advantage the 360 has in memory bandwidth (= eDRAM).

But if RSX is a 550MHz G70--which lines up with the E3 slides--then the 7800GTX 512MB = RSX.

For the fuzzy part: R520 has 16 Shader ALUs x 625MHz (10,000). Xenos, which is VERY similar in shader design to R520/R580, has 48 ALUs x 500MHz (24,000). If we consider a reasonable 25% average use for VS that comes to 18,000. From a shader perspective Xenos should be ~80% faster than the R520 in PS limited scenarios that fit the above scenario.

BUT these are all just numbers. REAL games use the features and design parameters and STRENGTHS of a design. e.g. 360 games will use some HOS and hardware tesselation and not worry about VS:PS ratios. PS3 games will leverage CELL for work and use shaders that make use of the miniALUs, etc.

The point being BOTH are great designs. Xenos is argueably a bit faster than R520, but R580 is basically Xenos for the PS with dedicated VS @ a 30% clock jump. R580 is probably a good 30-50% faster than Xenos... of course, as I mentioned, Xenos has more features.

Btw, something great in these pictures:

HDR + AA. It gives the game a "CGI" feel. Still not big on the animation realism or game balance BUT EA has done a killer job on this game. GREAT graphics, nice feel to it, playable, etc. Gloves, faces, sweat, bodies, shorts all look AAA+. Just a great game.

Really a shame in one way--to bad 360 devs did not have an extra 3 months with the final HW to make the launch titles look this good (well, a couple do look this good like PGR3).

With FNR3, GRAW, and Oblivion slated for the next couple months and DoA4 now out it looks like the 360 is getting a solid trickle of really good games. MS has done a good job in that respect. Nice launch + good flow of nice games to get people interested.

Excellent posts Acert93, bring it on :)