[mythtv-users] Optimal RAM Allocation for Intel

[Kirk Bocek]

On 10/23/2015 8:42 AM, Jim C wrote:
> Info on the net from Intel indicates that their modern GPU
> implementation like the HD 4600 is not dependent on reserved RAM (beyond
> what small amount is needed at boot), and that the DVMT is more
> important. The RAM for the GPU is dynamically allocated, based on need,
> up to the limit set in the BIOS for DVMT. Provided there is sufficient
> RAM to avoid contention when the dynamic allocation is needed the GPU
> will get what it needs. In my case, if the DVMT limit is set to
> "Maximum" the GPU could use up to 2GB of the 4GB available in my system.
> I don't expect Mythtv's video requirements to ever reach the 2GB level,
> so I've set the DVMT limit to Maximum to allow for best flexibility. The
> next step down from Maximum was 250MB, and that seemed a little low.
>
> The data also discussed the benefits of the Intel Unified Memory
> Architecture wherein the GPU has the same fast memory access bandwidth
> as the CPU, reportedly 25GB/s for the HD 4600.
>
> Don't know if this is helpful to others - just passing it along for
> consideration. Certainly, other CPU/GPU combinations could have
> different specifics.
>

That's probably a more modern implementation that that present in the 
ECS Liva: Bay Trail I think. Whatever memory you assign to video in BIOS 
is actually removed from system memory. I have a fixed 1.5GB available 
to Myth.