Hello,
I own a Gigabyte board and AMD's Phenom-II 1090T processor (I love my processor .
Recently, my RAM went bad and I have to buy new. The problem is that older RAM for which the processor is rated (DDR3 1333), is in short supply.
I contact Gigabyte and asked if I could under-clock my RAM (as opposed to over-clocking), the gentlemen said yes.
I've never touched the MBs overclocker, so the question I ask is is that a good idea? Do any of you have a system you've done it on? How would I regulate the voltage and stuff correctly?
I want a stable HW platform and don't want to go through a test of fire to determine the correct settings.
Thanks

I've underclocked computers, the only theoretical danger with RAM underclocking is the refresh may get too slow resulting in contents corruption. I wouldn't consider it a real danger, though.

The biggest thing, if your motherboard doesn't let you set the CAS timing, then get the faster memory with the fastest timings, and you shouldn't need to do anything. By default, RAM will attempt to run at that same system speed as the processor, so if you put DDR3 1600 in, it would automatically run at DDR 1333 speeds (and some even have CAS timings programmed that are more agressive as they go down in speed). Some people do this on purpose just because sometimes DDR3 1600 with the same CAS timings as DDR 1333 can run at more agressive CAS timings when downclocked, thus improving memory perfomrmance without overclocking.

It has generally been my understanding that your RAM must be at least as fast as the CPU, to avoid introducing wait-states in the CPU. But I know of no issues with RAM that is faster.

I passed a Maserati that was crawling down the I-75 toward Atlanta next to me a few weeks ago ...

You'd think that as long as you put the minimum ram in that it would be fine. I have seen it where fast ram just didn't work. Didn't bother to figure out why. May have been some oddity.

Generally you see some "known working tested" ram in manual or on web site(s) so I tend to just use those.

Making hard to find part is the reason we tend to have to buy a whole new rig sometimes.

Rated or advertised RAM speed in GHz is indeed a rated/supported speed limit, not a requirement.

The important thing is to use RAM that is compatible with your motherboard. As long as you do that, you should be okay.

Your motherboard's manual should tell you what its RAM specs are; generally, the manual can be obtained from the website of the motherboard's (not your computer's) manufacturer. You may have to open the computer to find out who made the motherboard.

Thanks, all.
I found that the faster memory is actually more expensive than the slower memory!
http://www.newegg.com/Product/Produc...82E16820231557
http://www.newegg.com/Product/Produc...82E16820231616
I'll tell you how it goes.
In case you're wondering why I want so much memory, it's because I want to create a program that will want lots of memory. No hints on what it does (it's all in my head anyway).

Thanks for the update.

Ram never seems to be too much ram.

Like @frankbell says, look at the manual for that motherboard and only use that RAM. I know some asus mbs have a RAM tester built-in to the mb and it will tell you if there are RAM problems with LED indicators. But you just want to buy the right ones.

You must think me really stupid/lazy to have someone *tell* me to RTFM and then not do it.
The MB supports the RAM the question was >--weather or not the processor could function with RAM that was too fast for it--< (that was *always* the question even the initial post was *supposed* to convey that).
Now either I'm an idiot communicator or perhaps you were typing after 23 hours of forced labour on windowz.

As to the original question, if you use RAM that is faster than the CPU's memory controller, then something called a "memory divider/multipler" will be used to make everything run smoothly. Example:
http://www.kitguru.net/wp-content/up...-MIT-CPU-1.jpg
This is usually done automatically so that your RAM can run at rated speed without you having to do anything. As long as the mobo supports the multiplier, the CPU will function fine, which is why people are telling you to RTFM.

If you use RAM that is faster than what the mobo supports with multipliers, it should fall back to safe settings. From my understanding, that doesn't always go smoothly though, especially if the mobo is set to try and use the EPP/XMP settings by default. That's why people are telling OP to RTFM and use rated memory speed that is supported by the mobo. I guess we could have a more advanced conversation about SPD and EPP/XMP and such, but that may be outside the scope of this thread (i.e. I'm too lazy to type about all that crap).

I disagree. The RAM should run at DDR-1600 speed if the board supports that multiplier. Base clock and HyperTransport remain the same.

I also think it's worth pointing out that there is usually a QVL (Qualified Vendor List) which is not in the manual, but is usually found on the mobo manufacturer's support page. Example: http://www.gigabyte.com/products/pro...support%20list
It's safest to stick with modules there, especially if you're the kind of person that might ask for support from the mobo manufacturer. Obviously, modules not on the list usually work, and manufacturers don't test every RAM kit out there (or update the list for RAM kits that come out after the board's release).

To summarize:
1. RTFM
2. Use RAM on the QVL if possible to be safest

I used to work at a big computer place. I've seen so many odd issues that I just go back to the phrase "logic is sometimes wrong."
Logically you'd think that faster ram would be great, even better, so much better that I'll try it. Then it doesn't work, and you play with it, you test, re-test, move swap then go get the right part.

You can fool with this stuff at home but you shouldn't chance this stuff at a company.

Sooo, will the central processor unit work??? At start up there is a very short pre-POST then the system moves on to POST then if OK it is assumed that the OS might begin to boot. Part of the pre-post is a small memory check. That check has to be OK in order to continue. While the CPU may have clock signals on it and power it will not as we know it, function if memory in pre-post or post fails.

Thanks for the pic. Mine bios is identical.
I plugged in the RAM and it works! (kinda)
I installed 32GiB. The bios detects 32GiB. But my linux kernel 4.1.15-r1 (Gentoo) does not. I used memtest first thing to see if my RAM was ok and it is, but what ever kernel the 4 year old memtest cd uses also does not acknowledge more than 24 GiB of RAM.
This is an interesting problem, any ideas?

1. How much ram DOES Gentoo (and memtest CD) see?
2. I assume you're running a 64-bit OS?