I just bought DDR3-1866 - I don't think my mobo is supporting it?

[CuriousMike]

I just upgraded my system from 8gb to 16gb - i purchased Corsair VengeanceLP 1866 2x8 memory.

My BIOS gives me *NO* specific option to use 1866.

If I load the computer a little, CPU-Z seems to indicate the memory is running at > 1800mhz ( or am I reading this wrong.)

It also seems to indicate it's no faster than 667*2 = 1333 mhz.
Can anyone decipher what my RAM is actually running at / can my system use it / is there a better utility to use to see whats going on?

 

[VirtualLarry]

I'm a little confused by your screenshots. Your "Memory" tab shows DDR frequency of 800Mhz, which is right for DDR3-1600 memory. Yet, your "Motherboard" tab, shows an H81 chipset, which, AFAIK, didn't allow DDR3-1600 memory. Or maybe that's just my experience with the G3258, and with a higher-spec CPU it will run with DDR3-1600. However, I don't think that it will go higher. You need a Z87 / Z97 chipset in order to overclock memory faster than stock.

 

[LTC8K6]

DRAM Frequency is 800mhz X 2 for DDR = 1600mhz

Your ram is running at 1600mhz, which is all your board can do.
However it is running at CL11, which is not the best. (cas latency)

You'd be better off getting some standard CL9 1600mhz ram.

 

[LTC8K6]

The MSI site says 1600 is the max memory supported for your board.

Bog standard CL9 1600mhz ram is what you need.

http://www.amazon.com/Crucial-Balli...1609DS1S00-BLS2CP4G3D1609DS1S00/dp/B006WAGGUK

 

[CuriousMike]

If I set the memory speed to AUTO in my bios, it picks 666.
When running CPU-Z with it at 666, the CAS latency is 9.

Assuming I'm not changing out the memory, should I prefer 1333@cas9 or 1600@cas11 ?

 

[flexy]

http://www.anandtech.com/show/7364/memory-scaling-on-haswell/3

1333@CAS9 or 1600@CAS11. This is pretty much the same. Choose which one works for you.

 

[flexy]

Chances are that your memory will also run at

800Mhz (== DDR 1600 at 9-9-9-24-41)
and up to
1000Mhz (== DDR2000 at 10-11-10-32-260) (If your board allows this ?)

Each 1T

(The JEDEC and XMP timings are usually on the more conservative side)

Don't know your board, if 800 freq (== DDR1600) all it can do, no reason to panic, just run it at 800 (DDR1600) and try to get CAS down, maybe it does CAS9 at that speed. If you look at memory scaling like in the AT article, differences are pretty much insignificant in real life performance.

 

[LTC8K6]

SPD for the ram is 1333 C9

http://www.corsair.com/en-us/vengeance-lp-memory-16gb-1866mhz-cl10-ddr3-cml16gx3m4a186610


SPD Latency
9-9-9-24
SPD Speed
1333MHz
SPD Voltage
1.5V

 

[CuriousMike]

Thanks for the details; I left it at 1600... using the AT memory speed graphs shown, it looks like 1333-C9 vs 1600-C11 is damn near identical - maybe a smidge more wins by 1600.

 

[LTC8K6]

1600 C11 just sounds so bad...

 

[MongGrel]

1600 C11 just sounds so bad...

+1

I still use 12 GB of this stuff on the main.

Runs well with low timings, even over clocks well Blck wise, which is one of the main reasons i bought it prior to the L5639, still does well with a X5680.

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231405

Someday I'll upgrade I guess.

 

[CuriousMike]

1600 C11 just sounds so bad...

I have never taken the time to truly understand CAS timings.

Going by the article posted above, unless I'm reading it wrong, the difference seems minute.
Correct me if I'm wrong.

 

[Ketchup]

Honestly, I haven't cared about timings since DDR (maybe a bit on DDR2). That was wgeb RAM timings were showing a substantial difference. Right now I am running very close to what you are, 10-10-10-27, without touching a thing.

 

[LTC8K6]

But there are a few decent differences in the charts between 1600/9 and 1600/11.

Besides 1600/11 is just gross.

 

[LTC8K6]

I have never taken the time to truly understand CAS timings.

Going by the article posted above, unless I'm reading it wrong, the difference seems minute.
Correct me if I'm wrong.

Wiki is your friend regarding cas timings.