ECC handling when shared between CPU and GPU

[bleekii]

I have an Athlon II x4 setup to use ECC and an integrated Radeon 3000 GPU 760G Chipset. Both are sharing 8GB of memory. Are the memory addresses assigned to the GPU using ECC? Or is there a separate memory controller on the GPU which ignores ECC?

 

[VirtualLarry]

The GPU in the chipset doesn't have a memory controller. It uses HyperTransport to talk to the CPU and its memory controller.

 

[bleekii]

That's what I thought, but do we think it's using ECC like the CPU? I know this is not an easy question to answer, but that's why I'm here asking it. Can anyone meet this challenge?

 

[VirtualLarry]

If the CPU's memory controller is using ECC, then the GPU's memory accesses will be to ECC-protected memory. HyperTransport has some sort of ECC or checksum as well, I think.

Edit: Another way of putting it is - there is only one memory controller (well, with two 64-bit channels). If ECC is enabled, then ALL accesses that go over that memory controller are protected by ECC. You cannot send some accesses with ECC, and some without.

 

[bleekii]

That makes sense. Thank you!