Intel’s Xeon W-3175X is an incredible CPU — not least because the price for the chip ($3,000) actually isn’t that bad compared with Intel’s historical prices for top-end Xeon parts. Corsair appears to have an idea what you can do with all that, ahem, cost savings. Why not pour it into some memory?
Listings for new DDR4 kits clocked at 4GHz have popped up on the company’s site. These new kits are specifically intended for the W-3175X and they pack a considerable amount of RAM into 12 sticks (both of the motherboards that support the W-3175X have 12 DIMM slots). The 96GB kit is $1,499 (12x8GB) while the 192GB kit is $4,000 (12x16GB). Lower prices are also available for lower clocks — the 192GB RAM capacity is available for just $1,585 if you’re willing to accept DDR4-2666.
It should be noted that according to Corsair’s own official price lists, you could buy 6x kits of 16GB DDR4-3600 C18 RAM and pay $1,350. Six 32GB DDR4-4000 C19 memory kits would cost you $2,754 when purchased for the price of $459.99 each.
Be Aware of Clock Limits
Let me say up-front that I haven’t tested Intel’s latest Core i9 28-core beast and am therefore extrapolating from the CPUs I have tested. On the other hand, there’s not a ton of information about overclocking the Xeon W 3175X or other high-core-count Intel CPUs ‘in the wild,’ either, mostly because the number of enthusiasts who can afford to purchase $1,800 to $4,000 CPUs is fairly small.
I’ve tested two Core i9-7980XE’s. The first couldn’t hold a DDR4-3200 clock with four DIMMs (32GB) out of eight slots in total, while the second couldn’t hold DDR4-3200 clocks with all eight slots loaded (64GB of RAM). I’ve had no trouble with the same RAM loadouts in other boards with other Intel CPUs and no issue with any of the Threadripper platforms I’ve tested in the same configuration. The problem appeared to be unique to the higher core count CPUs (and always required that I run these chips outside Intel’s RAM specifications). It’s possible that the later Core X CPUs have fixed this issue but I wasn’t able to find any information on the topic.
There’s generally an inverse relationship between the number of DIMM slots you load and the maximum RAM clocks your system can maintain. It also matters whether the RAM is single-sided or double-sided, with single-sided RAM configurations typically preferred for maximum stability.
It isn’t clear if the 96GB and 192GB kits go through additional validation specifically intended to clear them for operation on Xeon W-3175X platforms and motherboards. It also isn’t clear if the Xeon W-3175X tolerates high RAM clocks well as a general rule. Both of these are reasons to be careful when considering buying high-speed RAM. Corsair will have validated the memory with the motherboard vendors no matter what, but if the CPU is the limiting factor, there may not be much to be done on the motherboard side of things.
It’s also worth considering whether your workloads are particularly memory bandwidth limited in the first place. The 192GB kit for DDR4-2666 is $1,585. The same kit at DDR4-4000 is $3,000. If you don’t need the additional bandwidth, we wouldn’t recommend paying for it. Hat-tip to Overclocker3D for the news.