ryzen ram question

[blackestvoid]

what will be the theoretical max ram speed supported by ryzen ignoring motherboard capability?
any difference using ryzen 7 and 5 on same motherboard? got such thing as same ram speed can run on 7 but not 5?
if qvl is 3200mhz oc, if get 3600mhz, unclock any issues?

 

[LLCSG12]

Depends on luck

 

[blackestvoid]

what would be a good time frame to estimate the motherboard manufacturer give up bios optimization on ryzen and move to other chips?
given that the am4 is supposed to be compatible with all other chips released in the foreseeable future according to some reports, is it safe to get DDR4-4266 (or above) now and under clock it, just on tech considerations alone , ignoring luck and $$?

does under clocking DDR4-4266 to the motherboard qvl 3200 (oc) works? the ram would run cooler? does it work this way?
if $$ not a concern, it does not make any sense to get DDR4-2400 already right? just get whatever is the highest mhz without oc on the qvl list?

 

[singupingu]

Can you buy 4266mhz? Yes.
Will it work? Yes.
Any problem running at 3200mhz? No. But depends on your mobo bios and how optimized is it.
Will the ram run cooler? Probably but depends on your voltage as well.
Cost aside, is it feasible to buy 4266mhz for future proof? Personally, yes. Not sure how others will think.

In fact, you can run higher than 3200mhz by tweaking the bclk but only to a certain extent (5% I think) before the PCIE 3.0 bandwidth will drop to PCIE 2.0 bandwidth iirc.

Do find the crosshair vi hero thread, Macclipper posted a ram performance spreadsheet of how much others manage to oc theirs.

Sent from Overpowered Phone Mark III using GAGT

 

[Encrypted11]

Bclk overclocking is not safe on Intel pre-skylake and current Ryzen AMD, since PCIe domains are linked to bclk therefore overclocking the PCI bus has profound impacts on stability, with greater risk of data corruption.

http://www.anandtech.com/show/9848/bclk-overclocking-intels-non-k-skylake-processors-coming-soon

https://forums.anandtech.com/threads/ryzen-strictly-technical.2500572/
Technical review once embargo lifted.

The base-clock (BCLK)

Overclocking the base clock (BCLK) on AM4 platform is possible, however generally not recommended. This is due to its frequency relations with other interfaces, such as the PCIe. Unlike with Intel's more recent CPUs, there is no asynchronous mode (straps / gears) available, which would allow stepping down the PCIe frequency at certain intervals. The PCIe frequency relation is fixed and therefore it increases at the same rate with the BCLK. Gen. 3 operation can generally be sustained up to ~107MHz frequency and higher speeds will usually require forcing the links to either Gen. 2 or to Gen. 1 modes.

Unstable PCIe can cause various issues, such as system crashes, data corruption (M.2 SSDs), graphical artifacts and various kinds of other undefined behavior.

 

[blackestvoid]

assuming 3600 oc is on qvl list, imho it does not make much sense to get DDR4-3200 now and oc to 3600 when there are higher speed rams out on the market, there is almost no upside anymore

on the other hand getting 3600 without oc seems more reasonable as there is upside when bios get optimized subsequently

wonder why they don't test ahead with the highest speed ram availability on the market instead and uc?
for those getting the 7 the have the $$ and imho they rather spend more $$ for high speed rams and won't be happy getting low speed rams now and see it get overtaken

in the olden days rams are playing catching up to cpu but now it is the other way round
in fact logic would tell you to optimize for the best, if it doesn't work, go for 2nd best and so on, unless they had released 3, then 5, then 7 then it would had made sense...

in fact someone mentioned on reddit to get B-die and Samsung is the only one producing the 4000mhz stuff which makes more sense to go for higher speed