3 ms·

Is AVX-512 even useful in benchmarks? I thought it was mostly used for specialized workloads, and was basically useless for end users and gamers.

xlazom00 5y ago
Specialized like software video decoding and encoding,....
mhh__ 5y ago
Some parts of the game would probably benefit a bit from 512 (also remember that it isn't just wider, it adds a lot of new operations entirely), but there simply isn't enough parallelism in the main loop of a game to make all that much difference. Also "useful" and benchmarks do not mix well.
- leeter 5y ago
  For games generally those parts can be shifted to the GPU because they feed the rendering pipeline anyway. Doing so has other benefits of lowering latency for that data to be picked up by the graphics bits already there etc. Also the clock speed penalty for AVX512 is pretty steep so unless you're going to do a lot of AVX512 it really doesn't make sense either. Games generally aren't using double precision either which is the AVX512 bread and butter. To make it more fun even if they were... a 4x4 matrix is composed of 256bit elements so the vast majority of register usage wouldn't be 512 bit anyway. The main benefit would be the new instructions more than the register width. Long story short: Games generally aren't doing enough AVX to really benefit from it as implemented. They can be quite bursty in their use. Not to mention that Not every CPU even has AVX (because apparently Pentium Gold is a thing) even today. If Intel convinced AMD to pick up the 256 bit versions and removed the clock speed penalties I could see them getting more use. But at the moment it's really just a feature for the HFT market primarily and even they are extremely careful in use because of the clock speed penalty. To the point they will literally benchmark both ways to make sure the penalty is overcome by the throughput.
jeffbee 5y ago
AVX-512 is so useful in benchmarks that sites like Anandtech intentionally build their benchmarks without it, because the presence of AVX-512 spoils the whole horse race narrative they are trying to sell.

xlazom00 5y ago

Specialized like software video decoding and encoding,....

mhh__ 5y ago

Some parts of the game would probably benefit a bit from 512 (also remember that it isn't just wider, it adds a lot of new operations entirely), but there simply isn't enough parallelism in the main loop of a game to make all that much difference. Also "useful" and benchmarks do not mix well.

leeter 5y ago
For games generally those parts can be shifted to the GPU because they feed the rendering pipeline anyway. Doing so has other benefits of lowering latency for that data to be picked up by the graphics bits already there etc. Also the clock speed penalty for AVX512 is pretty steep so unless you're going to do a lot of AVX512 it really doesn't make sense either. Games generally aren't using double precision either which is the AVX512 bread and butter. To make it more fun even if they were... a 4x4 matrix is composed of 256bit elements so the vast majority of register usage wouldn't be 512 bit anyway. The main benefit would be the new instructions more than the register width. Long story short: Games generally aren't doing enough AVX to really benefit from it as implemented. They can be quite bursty in their use. Not to mention that Not every CPU even has AVX (because apparently Pentium Gold is a thing) even today. If Intel convinced AMD to pick up the 256 bit versions and removed the clock speed penalties I could see them getting more use. But at the moment it's really just a feature for the HFT market primarily and even they are extremely careful in use because of the clock speed penalty. To the point they will literally benchmark both ways to make sure the penalty is overcome by the throughput.

jeffbee 5y ago

AVX-512 is so useful in benchmarks that sites like Anandtech intentionally build their benchmarks without it, because the presence of AVX-512 spoils the whole horse race narrative they are trying to sell.