Does i7-4790 (non-K) support DRAM speeds higher than 1600MHz?

[DDimitrov]

I have an Asus H87M-Plus. Its H87 chipset is limited to DRAM 1600MHz. I would upgrade to Z87/Z97 if I know that my i7-4790 (non-K) would support higher DRAM speed then. This is the reasons I am asking this question.

I can't find any reliable information about that (whether i7-4790 supports DDR3 1866MHz or higher). According to this link it does:

https://www.guru3d.com/articles-pages/core-i7-4790-processor-review,16.html

But HWinfo says "DDR Overclocking = No" about i7-4790, so I am not sure if the information in the link above is correct.

Could anybody clarify?

Thank you.

[AlHill]

Your processor is a Haswell "refresh" processor:

https://ark.intel.com/content/www/us/en/ark/products/80806/intel-core-i7-4790-processor-8m-cache-up-to-4-00-ghz.html

It supports DDR3: DDR3-1333/1600, DDR3L-1333/1600 @ 1.5V

It is a non-K processor, therefore no overclocking is available.

Remember, your board's BIOS must support this processor. Check with your motherboard manufacturer to verify.

Doc

[DDimitrov]

Intel's official pages contains only the officially supported speeds. They do not say whether there are any explicit limitations above that. For example, the same info ("DDR3-1333/1600, DDR3L-1333/1600 @ 1.5V") appears on the i7-4790K's page too. However, i7-4790K supports higher DRAM speeds.

Also, the official page of my mobile i7-3610QM CPU says "DDR3/L/-RS 1333/1600". It is not an unlocked CPU. However, it supports DDR3 2133MHz in my Lenovo Thinkpad T530.

So, are you sure that there is an explicit limitation in i7-4790 in order to deny speeds higher than 1600MHz?

[AlHill]

"Intel's official pages contains only the officially supported speeds. They do not say whether there are any explicit limitations above that. "

That is correct. These are the officially supported speeds.

Doc

[n_scott_pearson]

Intel warranties only those speeds that it validates. Speeds above this level may work, but Intel hasn't validated it and does not guarantee that it will work. The only answer I can give it: try it and see.

...S

[DDimitrov]

I am not looking for official information from Intel, guaranteed by Intel or by anybody. I am looking for unofficial information from community members or users.

I could generalize my question - Does any Haswell non-K desktop CPU support DRAM speeds higher than 1600MHz? Or do all of them have explicit limitations by design in order to explicitly deny speeds higher than 1600MHz?

If somebody could confirm that another Haswell non-K desktop CPU (e.g. i7-4770, i5-4670, i5-4690, etc.) supports DRAM speeds higher than 1600MHz on a Z87/Z97 board, this would be an answer of my original question too.

Suggestions to try it myself are useless. If I was able to try myself, I would not have asked this question. I do not have a Z87/Z97 board to try with. I am not going to buy one, only to realize then that my CPU is limiting that.

Many people have asked similar questions in various Internet forums. Unfortunately, all the answers are totally useless:

= "1600MHz is enough, why do you need more?"

= "Buy fast RAM and tighten its timings instead"

= "Why don't you buy a K-version CPU?"

= "My K-version CPU supports that"

= "It should support that because my Sandy Bridge CPU supports that" :)))

= "I do not know, but I think it should support that"

... and other useless stuff.

This is the reason I am asking this question here.

[AlHill]

I cannot believe this. What good is unofficial information? It is no better than gossip or heresay, and does nothing positive. You want confirmation of speeds above 1600? Test them yourself.

I am certain you can find plenty of other places on the web for such a senseless discussion.

Doc

[DDimitrov]

When there is no official information, we look for unofficial information. What is wrong?

It would have been much simpler if the information I am looking for was official. Unfortunately it is not.

This is a community forum. Not an official support forum. So I am free to ask community members, no matter if you like that or can believe that.

Your answer was useless to me. I was asking whether there is an explicit limitation, but you answered what the guaranteed speeds are. I know what the guaranteed speed are. I was not asking that. Your answer was orthogonal to my question. I should add it to the list above.

[AlHill]

You already have the answer you want from guru3d. Orthogonal? <LOL>

Doc (not an Intel employee or contractor)

[n_scott_pearson]

This is all anyone can say: Once you go above the maximum speed that Intel validates (and warrants), all bets are off. If you are only going up a speed bin or two, usually it will work, but understand that there are no guarantees; you might get a processor that simply does not work at frequencies above the maximum.

...S

[DDimitrov]

Does this mean that the CPU has no explicit limiter - either by microcode or by other means? This is the question.

P. S. I know that there is no guarantied speed above the maximum validated by Intel (1600MHz), so I'm not expecting any warrants. Also, I'm not going to try very high frequencies. I already own an awesome kit of four Crucial Ballistix Tactical DDR3 @ 1866MHz and my intention was to use it at 1866MHz or try it at 2133/2400MHz. The problem is that I don't know if the CPU model is not explicitly limited up to 1600MHz. This would make a purchase of a Z87/Z97 board pointless.

[n_scott_pearson]

As far as I know, there were no explicit limiters. The memory buses will simply start locking up when unsupportable frequencies are attempted.

Since that's a Haswell Refresh processor, I recommend you get a Z97 board as some Z87 boards did not have BIOS support for these processors.

...S

[DDimitrov · Accepted solution]

In short - memory controllers of Haswell non-K desktop CPUs are not hard-limited to 1600MHz.

I just watched a couple of videos demonstrating BCLK overclocking of i5-4690 (non-K). In these videos the memory was running at 1866/1920MHz and 2133/2200MHz, which was the confirmation I had been looking for.

Thank you guys for your assistance!