AMD Code Support

[Computerrock]

Hello All!

I was wondering when/if GSdx will get code support for AMD processors (beyond SSE2) such as SSE3 or even SSE4a?

Looking forward to your response!

[smartstrike]

nope GSdx still loves SSSE3 and SSE4.1

there is an AMD processor can go w/ SSSE3 and SSE4.1 under development
until they released the "Bulldozer" based AMD processor.

[pcsx2fan]

I think SSSE3 and SSE4.1 only have small effect on FPS, the main FPS hit is AMD CPU doesn't support Denormals Are Zero from which PCSX2 benefit a lot, while Intel CPU does support it, I dunno if Bulldozer will support it.

It has to do with the fact that AMD chose not to support "Denormals Are Zero" optimizations. Intel chose to support this feature of the IEEE 754 floating point standard, which is a mode the PS2 itself utilizes; and it yields significant speedups in many games.

@ Moderator
It might be suitable to add emulation states on AMD CPUs to the FAQ page, cuz people kept asking similar questions since a long time ago. Useful information can be derived from Issue 926, such as:
http://code.google.com/p/pcsx2/issues/detail?id=926#c3(as to SSE3 and SSE4A)
http://code.google.com/p/pcsx2/issues/detail?id=926#c10(as to SSE3)
http://code.google.com/p/pcsx2/issues/detail?id=926#c11(as to Denormals Are Zero)

[haxor]

PCSX2 is still primary a basicly Intel program and kinda "hard" work to optimize for AMD procs. So...

no topic

[Shadow Lady]

Hello All!

I was wondering when/if GSdx will get code support for AMD processors (beyond SSE2) such as SSE3 or even SSE4a?

Looking forward to your response!

Problem is SSE3 and SSE4a do not add anything that PCSX2 could use (SSE3 is also available on Intel processors just in case you're thinking PCSX2 is made for Intel only).

The SSSE3 instruction barely adds any speed generally, it depends highly on the game and scene that is playing and it doesn't exactly make games twice as fast or anywhere close to that anyway.
SSE4.1 is a little better but still depends on the game and it won't add that much speed, according to the PCSX2 team currently SSSE3 and SSE4.1 add a 5-10% of general performance and that's including PCSX2 which has a few SSE4.1 instructions, GSdx is less than that.

As for AMD support? The emulator runs with AMD processors, doesn't it? so they're supported . Maybe when AMD starts adding more useful stuff it will be better optimized (AMD Bulldozer will have SSE4.1 as mentioned before for example).

Offtopic: I actually can't wait for new AMD offerings so when people ask about SSE4.1 we can just say "well your old AMD CPU doesn't have them but new ones do so get a new one! ".

[rama]

Agreed fully.
Bring on the new chips already, AMD

[Computerrock]

Thank you for the quick response,
I myself am waiting for Bulldozer to come out! Hopefully it will provide the competition needed against Intel so that we can see leaps in technology, like when AMD took the performance crown with the 64 Athlon.