CPU prices starting to fall ( for some processors )

[petrw1]

I'm in need of a new main PC...and because I "had to" work this year (they gave me an offer I couldn't refuse) I have little extra "play money" and plan to build relatively "elaborate": big CPU, lots of RAM, big GPU.

Due to winter holiday plans I either need to buy in the next month or wait until the Spring.

Are there any big announcements expected soon that suggests I should wait?

[M344587487]

The CPU milestones I'm aware of are:

• intel ramping up production of coffeelake, production is still low but improving, maybe there will be a decent price cut for Ryzen in response (or coffeelake will be easier to acquire, or maybe you could snag some cheap skylake/kabylake if they get priced to sell). Consensus seems to be that coffeelake will have proper production levels in Jan/Feb: https://imgur.com/a/ozrEU
• AMD releasing Zen+, consensus seems to be March at the earliest, probably April, although some rumours suggest February. I have a feeling AMD will pull an intel and do somewhat of a paper launch to try and put a damper on coffeelake.

If you know what sort of system you're going to get, I'd buy compatible RAM now even if you don't buy the rest, prices are going to keep going up. As for GPUs, prices have been coming down a little, but many are still way over MSRP. How big are you going, Titan V big?

[petrw1]

Originally Posted by M344587487

The CPU milestones I'm aware of are:

• intel ramping up production of coffeelake, production is still low but improving, maybe there will be a decent price cut for Ryzen in response (or coffeelake will be easier to acquire, or maybe you could snag some cheap skylake/kabylake if they get priced to sell). Consensus seems to be that coffeelake will have proper production levels in Jan/Feb: https://imgur.com/a/ozrEU
• AMD releasing Zen+, consensus seems to be March at the earliest, probably April, although some rumours suggest February. I have a feeling AMD will pull an intel and do somewhat of a paper launch to try and put a damper on coffeelake.

If you know what sort of system you're going to get, I'd buy compatible RAM now even if you don't buy the rest, prices are going to keep going up. As for GPUs, prices have been coming down a little, but many are still way over MSRP. How big are you going, Titan V big?

Thanks.....
I've always been an Intel guy for processors.
Why would RAM go up?
In the order of GTX-1080-Ti big.

[mackerel]

There's been a shortage of ram for over a year now, with prices creeping up. News is Samsung are putting more production in place but it may be some time before that takes any effect, and even then it is not guarantee of a drop.

CPU wise, for gaming and general purpose consumer stuff the 8700k is probably the one to go for. For prime finding, running 6 fast cores with only two ram channels could limit its potential.

For an outside consideration, there's the 7800X at 6 cores, and possibly cheaper than the 8700k although the mobo will cost more. You get quad channel ram with this, although the new L3 cache structure on these might not play well with various use cases so you might not see the performance expected.

[petrw1]

Strictly general purpose household stuff and prime finding....no gaming.

Thx

[mackerel]

I forgot to mention, the 7800X also has AVX-512 so once much of anything uses it, that might help also. Otherwise I think those two are still the top choices. You can buy more cores, but then price really starts to go up.

[M344587487]

Originally Posted by petrw1

Strictly general purpose household stuff and prime finding....no gaming.

Thx

Purely for prime finding you'd go 8100 or 8400 (possibly 7800X, I can't comment), as mackerel says I think 8700k would hit the RAM limit easily. GPUs is a more interesting question, as the main weakness of Vega is gaming, and compared to Nvidia it's a beast at certain forms of compute. I've asked for benchmarks of 1080ti of gpuOwl for comparison: http://www.mersenneforum.org/showpos...&postcount=241

[M344587487]

I'm an idiot for thinking nvidia cards running OpenCL would be a good comparison, so as penance I've trawled up some CUDALucas benchmarks. CUDALucas does LL and gpuOwl does PRP, but I think the tests are comparable (within 3% if some post I read on this forum at some point is to be believed). Unless there is a CUDA PRP test I'm unaware of, these are the prime finding programs you'd probably use, for Mp anyway.

1070 CUDALucas bench: http://www.mersenneforum.org/showpos...postcount=2608

 Device              GeForce GTX 1070
Compatibility       6.1
clockRate (MHz)     1708
memClockRate (MHz)  4004

  fft    max exp  ms/iter
 2048   38492887   2.2206
 4096   75846319   4.4940
 8192  149447533   9.5765

1080TI CUDALucas bench: http://www.mersenneforum.org/showpos...postcount=2572

Device              Graphics Device
Compatibility       6.1
clockRate (MHz)     1582
memClockRate (MHz)  5505

  fft    max exp  ms/iter
 2048   38492887   1.3294
 4096   75846319   2.6252
 8192  149447533   5.4126

Vega 64 and older gpuOwl PRP bench: http://www.mersenneforum.org/showpos...&postcount=230

Originally Posted by preda

Some performance data that I see on my hardware, at 4M FFT (adequate for the current wavefront around 76M).
...
Vega64: 1.63 ms/it (under-clocked to 1401MHz for thermal reasons)
FuryX : 1.89 ms/it
R9-Nano: 2.05 ms/it (the card downcloks itself for thermal reasons)
390x: 2.17 ms/it

[Mark Rose]

Originally Posted by M344587487

Purely for prime finding you'd go 8100 or 8400 (possibly 7800X, I can't comment), as mackerel says I think 8700k would hit the RAM limit easily. GPUs is a more interesting question, as the main weakness of Vega is gaming, and compared to Nvidia it's a beast at certain forms of compute. I've asked for benchmarks of 1080ti of gpuOwl for comparison: http://www.mersenneforum.org/showpos...&postcount=241

Go with the 8100. It's paired with DDR4-2400 and is only slightly bandwidth starved.

The six cores in the 8400 are going to be very much bandwidth starved by having only two channels of DDR4-2666.

Another option is the 8350k, which can support overclocked memory. Pair it with DDR4-3200 or so. But it won't be as cost effective as the 8100 with a cheap non-Z motherboard.

[mackerel]

Note the request was for a "big CPU" so I don't think we should be limiting to the quad cores even if we potentially hit limitations specifically for prime finding, it would be nice to have for general use. If not budget constrained, I'd still aim for an i7, in either of 8700k or 7800X.

[VictordeHolland]

Originally Posted by petrw1

In the order of GTX-1080-Ti big.

Good choice, I'm very happy with my GTX1080Ti with ASUS STRIX cooler (as you might have read in another thread).

If you want a single PC with bad-ass specs, I would go with a i7-7820X if your budget allows for it (8 cores @3.6-4.3GHz)