Question I accidentally overclocked Kingston JEDEC 5600MB/s --> 6400MB/s

[mmaenpaa]

I was looking for 16GB JEDEC 5600MB/s memory on our distributor webshop.

(I use jedec memory for business workstations & non gaming private customers)

I found KVR64A52BS8-16 (SPD is programmed to JEDEC standard latency DDR5-6400 timing of 52-52-52 at 1.1V)

At that time I did not notice/care about the CUDIMM word in the description. I was just like "6400MB/s & jedec, that's nice."

I tested a pair of these with this combo:
ASROCK B850 Pro-A WiFi (bios 3.50)
AMD Ryzen 9 9950X3D

And then I was greeted with this upon post.
AMD platform is not compatible with CUDIMMs but it boots anyway at 5600MB/s and works fine (8000&9000 series in bypass mode).



While I was at it, I thought why not try it with 6400 profile. I changed profile in bios to this PC5-6400 jedec.
Seemed to be working OK (ran Karhu for a 15 minutes etc.)

After my curiosity was satisfied I decided put original 2 X KCP556UD8-32 (KINGSTON 32GB DDR5 5600MT/s) back in.

I booted PC and checked memory speed, it was still using 6400MB/s JEDEC profile settings. Just for kicks (yeah, I know...) I decided to see if it holds.
So far 56 minutes of KARHU has passed.

A nice 10% boost (on MaxxMem) while using 1.1V voltage. Of course assuming it *really* is stable.
(I do not have time for proper testing with this PC as I need to get it ready for delivery.)

 

[igor_kavinski]

Yeah, I also "discovered" this trick by mistake. Run a good quality RAM stick at its rated higher speed. Swap it out and put in slightly lower quality kit and the mobo "thinks" nothing has changed (even though it should detect it's a new kit and should apply default settings) and the slower kit is boosted to higher speed. Happened with my 8200 kit that boosted a 7200 kit to 8200 on my 245KF. I later messed with the RAM speed and timings and now I can't get it to run at 8200 anymore. So I will need to put in the original 8200 kit to trick the mobo again!