Hacker News Reader

Comment by dotnet00 | Hacker News Reader

I don't necessarily agree on looking at pricing that way. One reason being that the 24 core part is 8 ccds with 3 cores each, while the 7950x is 2 ccds with 8 cores each, so the threadripper is able to go with much lower quality chips which would have otherwise gone in the bin.

View on HN

Even if it uses chips with defective cores, it's four times the silicon. The 24-core Threadripper is actually greatly advantaged compared to the 7950x for the right workload. There is four times the L3 cache, and four times the bandwidth from the chiplets to the io die. If you just needed a place to sell chips with a core defect, there are Ryzen SKUs for that.

What do you think the appropriate way of looking at pricing is? Once you get beyond 8 cores, your ability to saturate the CPU comes down to very specific parallelized workflows that can benefit close to linearly from extra cores. If you have that kind of workflow (render farms, encoding, etc) then the marginal cost of a CPU feels relevant.

I'm sure there are other workflows, especially in the cloud where you are rending out fractions of a CPU. But for individual professionals, what else besides marginal core cost would you consider?

You mean the Threadripper has a lot more cache on the 24 core part so it's going to be much better in those workloads that fit into its cache but not into the 7950x's?

Don't you incur the cross-CCD latency every time you hit the 3D L3 cache anyways?

Still, that's good info., I must have missed that part where they are doing their CCD layout like that.

I don't think you get a cross-CCD hit for 3D v-cache - rather the entire L3 cache for that chiplet is slightly slower (latency wise) - https://chipsandcheese.com/2022/01/21/deep-diving-zen-3-v-ca...

Threadripper doesn't have V-cache though.

imagine if it had a shared cache....

A shared cache would be slower. Better for some apps, worse for others.

Reply on news.ycombinator.com