To be 20% more power efficient per clock than Gekko, Broadway would need to run at 7.1W typical/12.0W max. The 970FX does 11W/13W at 1.0GHz. It also would need to incorporate all of Gekko's additional architecture. I just don't think a 970 can emulate 750 hardware at just over twice the clock speed. Developers were writing code right down to the assembly language of Gekko and any differences would make Gamecube games incompatible.
Gamecube-PPCDBK-EFB486X3- 9314
Wii - BWYC-72914-9316
Do these IBM CPU codes mean anything to anyone?
the first three digits of the numerical parts correspond to the known GC CPU clock speed and the rumored Wii one. So unless this is some really weird coincidence, Wii's CPU clock speed is apparently confirmed.
So you're saying that software written for a G3 will run on a G5 with no modifications?970 wouldn't need to "emulate" the 750 because they are both PowerPC processors and run the same instruction set. There are probably slight incompatibilities and Gekko has extra instructions but it would just need a modified version of the 970 (probably not even modified that much).
There would be different latencies in instructions but that won't break software but could impact performance.
http://developer.apple.com/hardwaredrivers/ve/g5.htmlApple's Developer Site said:Generally speaking, it is a mistake to tie specific software features to certain processors. Doing so is necessarily fragile because as new processors come out your code will not grow to take advantage of them. In certain cases, G5 specific code might be required to work correctly on the next processor as well. One example might be using dcbz, for which the size of the cacheline is critical. Code that assumes that only G5 has a 128 byte cacheline, and all others are 32 bytes will fail if another processor arrives that no longer calls itself a G5, but which has 128 byte cacheline size.
the first three digits of the numerical parts correspond to the known GC CPU clock speed and the rumored Wii one. So unless this is some really weird coincidence, Wii's CPU clock speed is apparently confirmed.
So you're saying that software written for a G3 will run on a G5 with no modifications?
I'm sure developers got down to the point that they were using commands that were valid on a PPC 750 but are not on a PPC 970. This would cause problems when trying to run said code.
Which can work on pairs of single-precision floating-point numbers stored inside a single double-precision register. Kind of the poor man's SIMD, but still effective for the intended applications at little extra cost.Gekko's SIMD instructions ?
As far as I know, it has no SIMD capabilities, just an scalar FP execution unit..
You can find more info here: http://pabut.homeip.net:8000/yagcd/chap3.html#sec3.4I think I remember them talking about the SIMD capabilities, but I can't remember much of it anymore. It definitely has SIMD tho.
That image is right in the thread a few pages back.
hi followed this and other wii threads with interest thought id add my pennys worth. iv been looking for pics of wii chips with the shields off and as i thought the 1 tsram-r is embedded on to the same die as hollywood so is it 3mb catch in hollywood and 24mb 1tsram-r ON hollywood if so i dont believe for 1 second that 24mb 1tsram = 3.9gb bandwidthI'm surprised that no one has managed to post a link to this yet.
http://xs.to/xs.php?h=xs309&d=06476&f=20061124willchip.jpg
In any case the 7xx series core (Broadway) is incredibly tiny at 90nm. They could have easily gone SoC with this setup i.e. Hollywood + Broadway on the same die with the ~24 MB of 1T-SRAM on the ASIC package (as it exists now)... Makes me wonder if a ~65nm refresh will allow them to do this.