Hacker News Reader

Comment by GordonS | Hacker News Reader

It's interesting that the EPYC 7601 comes at a significant premium to the EPYC 7551P - double the price for a 200MHz base clock increase and dual-socket support. Question for those more knowledgeable on data centres - is the modest performance gain and increased density worth it for the cost?

View on HN

You don't buy a CPU alone. You buy a whole server. If the CPU increases 1000$ in price to gain 10% performance but the complete server already is 20000$, it's quite worth it to go from 20000$ to 21000$ for 10% of performance.

Also if you factor in a performance critical software for 100000$ that runs on that single node, you will buy the fastest hardware that you can get for a few thousand dollars more.

It doesn't totally negate your point, but paying $20k for a server is far from the norm, and I imagine a dual-socket motherboard also comes at a significant premium.

It depends on so many factors (hosting costs, design/availability of motherboards/servers, workload easily parallelizable across multiple servers, etc)

But Intel does the same. The 2-socket http://ark.intel.com/products/91768/Intel-Xeon-Processor-E5-... is superior in every single aspect to the 4-socket https://ark.intel.com/products/93796/Intel-Xeon-Processor-E5... but yet the 4-socket CPU is priced 1.6× higher...

> The 2-socket... is superior in every single aspect to the 4-socket...

Except density :) If both Intel and AMD do this, then I guess data centre admins do see the increase in density as worth the extra cost.

Does this increase in density have yet more additional cost implications in terms of cooling?

8S and 4S servers (or even bigger systems) have always been extremely expensive; 2S has been the norm for many years. Being able to stuff two 2S nodes in 1U pretty much negates the density advantage of a 4S system, without the quadratic increase in price that a scaled-up systems have. (Also, density is usually limited by power dissipation, so the lowered power efficiency of bigger systems becomes an additional con there.)

If you have limited physical space, I can see taking the premium in cost for things like storage or CPU power. Larger data centres also have the capital to spend to squeeze out the cost of those components.

Heh, except for the most important part of having twice the performance, twice the cores, and twice the ram inside a single node with a single kernel.

Not all tasks can be split across nodes. If you need 4TB in ram you have to get the more expensive quad socket CPU.

The differences between the 7601, 7551 and 7501 stuck out at me as interesting. The 7601 is at least $1300 more expensive for 200MHz more clock and 10W/25W (???) more TDP. Is that an artificial distinction, or do such high-TDP chips have a worse yield?

It comes down to binning of the same chip for AMD and there are people out there willing to pay the 100% extra for a 10% improvement.

Reply on news.ycombinator.com