3 ms·
To me, it does seem really weird that they opted to downclock the entire CPU rather than increase the latency of the instructions that caused overheating. That
by adgjlsfhk1 5y ago
To me, it does seem really weird that they opted to downclock the entire CPU rather than increase the latency of the instructions that caused overheating. That feels like it would have been a much less disruptive solution that would work strictly better.
- colejohnson66 5y agoIf you increase latency, the ROB fills up quicker, and could get full which would back up the pipe. It makes sense why they’d choose to use the default “downclock on overheat” rather than add more circuitry to deal with that specific issue.
- BeeOnRope 5y agoWhen the first AVX instruction is run after a long period of no AVX, something like this does happen: the dispatch of instructions is throttled to 1 out of 4 cycles while some AVX instruction is in the scheduler (this applies to all instructions, not just AVX). This is severe restriction: even if could be limited to AVX instructions, running at 25% of the throughput would make AVX pretty useless. This state persists only for a short time until a voltage and possibly frequency transition can be made at which point everything can run at full speed (albeit sometimes at a reduce frequency).