[Openchrome-users] problem on sp8000 with 720x576Noscale

[Thomas Hellström]

Hi.

druyts pascal wrote:

>
> Comming back to memory troughput, I tested it with memtest which shows 
> 184MB/s. The xorg log shows 221 MiB/s as the best copy with SSE. Those 
> figures look small to me as with DDR400 I would expect 1.6GB/s 
> (400Mhz, 32 bits) and this indeed is the king of figures I get on my 
> backend. Does this show I have a problem with the memory (hardware, 
> bios setup?) or is it normal for the SP8000? If so, does it show that 
> the frontbus of the SP8000 is slow and that DDR400 are useless? I 
> could not find any specs for the memory bus.
>
>
I can just briefly comment on the throughput. The figures you see in the 
X server logs are when the processor copies data from system memory to 
framebuffer memory. It's a normal figure. This has nothing to do with 
the speed with which the video chip reads picture data from the 
framebuffer memory. That should be close to DDR400 speed and it is 
impossible to measure that throughput.
I don't think your problems are bandwidth related.

/Thomas

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