Confused about RAM speeds on an H87 Motherboard

[VMaxMuffin]

Hi everyone,

 

I'm looking at building a mini-ITX gaming rig (see this post here) and will probably be going with an i5 4440 or 4570 with an H87 motherboard, at this stage probably an MSI H87I but I have a question about RAM.

 

At the moment, I can get 2x4GB G.Skill Ares RAM in either 1600, 1866 or 2133mhz versions for the same price of AU$105. Although my embedded PCPartPicker build has the 1866 selected, I am thinking of going with either the 1600 or 2133 simply because they're a red-orange colour, rather than blue and I've changed my mind about what colours I want . However, I am a bit confused about how RAM speeds work on H87 motherboards.

 

Firstly, I understand that all non-Z Intel motherboards have a maximum supported RAM speed of 1600mhz. However, they also often support XMP, which I don't understand because I thought that was only to allow the RAM to run at speeds higher than 1600mhz. Does this mean it's not "supported" but "can be done"? Or is there something else about XMP which it is used for in this scenario...

 

Also, at the moment I am thinking of buying the 2133 anyway because then if I upgrade to a Z-motherboard in the future I can utilise the higher speeds (may as well - seeing as its the same price) however I know that this RAM also has higher CAS latency (11 for the 2133 vs 9 for the 1866 and 1600). I think though that if I have to run the RAM at 1600 due to using the H-chip, the CAS latency will also drop, but is this the case? Also, if it won't, how much of a difference would it make having the "actual" 1600 RAM running with CAS 9 vs having the 2133 RAM running at 1600 with CAS 11?

 

For reference, here are the three RAM kits I'm talking about:

 

1600mhz: G.Skill Ares F3-1600C9D-8GAO 8GB (2x4GB) DDR3

1866mhz: G.Skill Ares F3-1866C9D-8GAB 8GB (2x4GB) DDR3

2133mhz: G.Skill Ares F3-2133C11D-8GAO 8GB (2x4GB) DDR3

 

Hopefully you can answer my questions

[SirRoderick]

You should just go for the 1600 kit really, the speeds don't matter all that much these days (pretty much the least significant part of your PC)...and next time you upgrade you're probably looking at DDR4.

 

As for the whole "supported" thing, that's exactly what it means IIRC. You CAN run them faster, you just need to fiddle with the BIOS a little.

[dizmo]

A lower CAS is actually better. I'd go for the 1866mhz as long as it's supported by the board.

The difference is minimal at best, but I usually go for 1866mhz for peace of mind.

[VMaxMuffin]

Thanks for your replys

 

You should just go for the 1600 kit really, the speeds don't matter all that much these days (pretty much the least significant part of your PC)...and next time you upgrade you're probably looking at DDR4.

 

As for the whole "supported" thing, that's exactly what it means IIRC. You CAN run them faster, you just need to fiddle with the BIOS a little.

 

But is there any reason I wouldn't get the 2133 given that the price is exactly the same?

 

A lower CAS is actually better. I'd go for the 1866mhz as long as it's supported by the board.

The difference is minimal at best, but I usually go for 1866mhz for peace of mind.

 

I know lower CAS is better, but 1866 also isn't supported by the board (only up to 1600) - so my question is would the CAS speeds go down to 9 by running the 2133 at 1600 speeds?

[SirRoderick]

Thanks for your replys

 

 

But is there any reason I wouldn't get the 2133 given that the price is exactly the same?

 

 

I know lower CAS is better, but 1866 also isn't supported by the board (only up to 1600) - so my question is would the CAS speeds go down to 9 by running the 2133 at 1600 speeds?

 

 

I actually did not realise they are the same price. In that case get the faster one, literally no downside. Even if you run them full tilt the latencies will not give you a problem, but I can't tell you how much latencies would drop if you run it at 1600. At any rate, you wouldn't notice the difference.