DOS ain't dead - Incredibly slow MMX?

Incredibly slow MMX? (Developers)

posted by mht , Wroclaw, Poland, 21.03.2009, 12:57

While looking for something else, I found the following in http://www.microsoft.com/whdc/archive/GDInext.mspx:

Writes by the CPU to video memory surfaces are also acceptably fast--thanks to write combining--and throughput is typically 200 MB/s on the latest AGP (accelerated graphics port) systems. Read speeds, however, are terrible, typically maxing out at 12 MB/s on the latest AGP systems. This read performance is anathema to most MMX routines, which are typically read-modify-write by nature of their vector processing. It is also a problem for any routines that must explicitly do read or read-modify-write operations, such as is the case with almost all image processing filters or Microsoft DirectX Transform plug-ins.

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Complete thread:

Incredibly slow MMX? - Laaca, 02.03.2009, 21:15 (Developers)
- Incredibly slow MMX? - Rugxulo, 04.03.2009, 03:01
  - Incredibly slow MMX? - Laaca, 04.03.2009, 13:26
    - Incredibly slow MMX? - Rugxulo, 04.03.2009, 23:50
- Incredibly slow MMX? - Japheth, 04.03.2009, 17:55
  - Incredibly slow MMX? - Laaca, 08.03.2009, 22:04
    - Incredibly slow MMX? - Rugxulo, 09.03.2009, 00:33
    - Incredibly slow MMX? - mht, 21.03.2009, 12:57
- Incredibly slow MMX? - DOS386, 22.03.2009, 06:11