Laskos wrote: ↑
Tue Jul 09, 2019 12:01 pm
Yes, I speculated on the issue that 3000 series 32 core Threadripper is rumored to fix the issue, and then, not having a clear budget, might be a "best buy". But such a system will be in $5000 range, if coupled with other powerful hardware components. There are "best buys" and "hard to get even better buys", and now that Uri wrote about $2500 budget, this one is ruled out.
There is much speculation in all this. Are you sure that "the coolest running and fastest chiplets will be found on the 3950X"?
No I don't think the 3950X will be getting the best chiplets! Those will be reserved for Epyc CPU's since they are higher priced SKU's with much greater margins. But, I am sure the 3950X will be getting better chiplets than the lower tiered CPU's. The question is: How much better will they be?
Are you sure that 3950X with same reasonable cooling can match 3900X on average clocks on all running cores?
I doubt that will be able to, but your assumption that it will be limited to it's base clock seems absurd. I've seen benchmarks where all cores boosted to over 4Ghz for the entire duration of the test which was in excess of 10 minutes. So, I think it's a fair guess that the 3950X won't be limited to just it's base clock while running an AB chess engine. Since there is an easy way to find out what the truth of the matter is, I suggest it's smarter to wait if you need/want the extra computing power and then there will be no need to speculate!
Nobody knows. Also, L2 + L3 cache per core in 3900X is about 30% higher than that per core in 3950X (that is not a speculation), and for a cache intensive software like Stockfish, it does matter. All in all, I would bet that per core performance with SF on all cores will be higher in 3900X versus 3950X, having similar cooling and temperatures. And the reasons to spend $250 more on 3950X compared to 3900X are debatable ($150 seems to be a fairer price addition).
If it were the case that the price for the entire system was $500 for a 3900X and $750 for a 3950X I might agree with you. But that's only the case if you already own a system and it will accept a 3900X or 3950X as an upgrade with the rest of the system unchanged. If you are building it from scratch and the cost is $2000 for a 3900X system and $2250 for an identically configured 3950X system then your analysis of the true value of a 3950X seems flawed. In this example it will need to boost the NPS by 12.5%. If it can't achieve that then I suggest they won't be selling many of them in the chess community. I have good reason to believe it will exceed a 12.5% increase in NPS by a wide margin. So, I'm willing to wait and see.
A good chunk of applications, Leela included, depends more on 1-2 core performance than that on all cores. Yes, one can go back and boost those very fast 1-2 cores on 3950X, keeping the other on base clock, but it's not what we are usually doing when mixing up full CPU and 1-2 core performances. Let's see, I am speculating a bit too.
There is no need to go back and boost anything on the 3950X as precision boost will do that on the fly for you and it will do two cores to it max boost clock and single cores to more than the boost clock for short periods. So you don't have to worry about such things, if set it up properly the MB/CPU will do all that for you. And then when it sees a workload that needs all cores it will automatically drop the clocks to maintain the power target as long as it doesn't bump the thermal limits or CPU core voltage limits. I think you're trying to make it more complicated than it is.
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