FistTimeRight,
How did you manage to copy data to gpus seperately? From your
question I assume that you have some data on 1 gpu and you
want to copy it to the other gpu without going to system memory,
which implies that you have some data on one gpu and other one
does not. According to my observations that can not be case with
current drivers.
I also have 4870x2 and even though cal/brook reports two gpus,
you can not allocate resources on just one of them. It looks like
when a stream allocation is requested, allocation occurs in both
GPUs memories, since both available local GPU memory decreases.
Which is bad because although there is 2G byte physical memory,
you are able to use just 1G bytes.
I suggest you add some calDeviceGetStatus before and after resource
allocations and check for yourself.
And just in case I am wrong, can you explain how did you manage to
allocate resource just in one GPU?