25
3
I was browsing for a RAM upgrade earlier for my system, and came across 'AMD-only' RAM (aka, RAM that only works on AMD chipsets). This RAM can easily be found on sites such as eBay, and seems to be slightly cheaper than 'normal' RAM.
The RAM prompts a question: is this RAM really restricted to AMD chipsets?
When considering RAM for a system, there are certain considerations to make such as:
- Speed (1066MHz, 1600MHz, etc);
- CAS (latency, lower is better);
- Generation (DDR2, DDR3, DDR4, etc)
However there is usually no such consideration as chipset compatibility. Sure, it's possible to guarantee that a given stick of memory will work if it's within the bounds of the chipsets listed in the information given by the seller/manufacturer.
For instance if a series of chipsets supported RAM between 1600MHz and 2400MHz, with 9-12 CAS, and on DDR3, it would be possible to list a product as being fully compatible with that series of chipsets if the said RAM was 2000MHz, 10 CAS, and DDR3.
I suspect that's partially the story here. However, is it possible at all for a given stick of memory to be 'AMD-only' or 'Intel-only', and if so, how?
Just study any IC's data sheet and you'll notice that there are many more important details, which are usually not mentioned (or else consumers would get even more frustrated than they are). Tolerance values for voltages, power consumption, signal edge steepness, 0/1 threshold levels etc are among the parameters which are usually standardised. I don't know the details in this case but could imagine that if AMD allows for higher tolerance values, this allows vendors to sell chips which they would usually have to destroy because they're slightly out of specification. – Run CMD – 2016-03-03T16:01:25.790
1It is a "thing" in that AMD has one set of SPD extensions and intel has another, but as far as I know, they both should have the basic fallback to DDR2 jedec information. Possibly the reason they are marked AMD only is that they are presuming the end-user cannot manually set timings if the SPD info is not honored (major box vendors have poor manual BIOS configuration support). I won't make an answer though because I don't have good evidence for this. – Yorik – 2016-03-03T16:12:24.653
What makes you think these modules only work in AMD systems besides a description created by the seller? What does the AMD description say? – Ramhound – 2016-03-03T16:15:40.907
1@Ramhound That's my point though, I suppose my actual question is 'is this just sellers trying to market the RAM modules, or is there another reason?'. – AStopher – 2016-03-03T16:18:27.883
@ClassStacker So they could just be purchasing 'defective' RAM that are only defective as their tolerance values are out-of-bounds for Intel processors, but not for AMD processors? Interesting if true & could also explain the cheaper price. – AStopher – 2016-03-03T16:20:00.727
1I was wildly guessing, but if it's the case, then yes. Similar to how they introduced triple core processors -- the probability of one core being defective is high enough to consider not throwing that quad core away. But it may also be the case that the RAM was supposed to be faster or something, and that you cannot rely on its SPD or it was disabled. Which is basically a similar case -- a piece of silicon which does not fully meet its specification. – Run CMD – 2016-03-03T16:44:22.683
@cybermonkey - I noticed errors on product descriptions on Amazon daily. Uninformed people sell stuff they don't need, uninformed people write descriptions for products they are selling, an error in a product description isn't unheard of. – Ramhound – 2016-03-03T17:50:55.807
1I don't know how it's possible, but it did bite me. My brother bought 2x4GB sticks of DDR2 memory, because he wanted to use it on gigabyte ga-g41m-es2l motherboard, which does support 8GB DDR2 RAM. And...it didn't work because he bought one for AMD and not for intel. It posts, the RAM is detected (all 8GB of it) and then it just reboots a few seconds later, sometimes with some visual glitches. We also tried to decrease the frequency and set worse timings in BIOS still on old RAM, and try again, but that didn't change anything, that seems to exclude it being slower. And it works on P31 chipset. – barteks2x – 2018-04-14T13:43:59.270