ASUS P8Z68-V LX LGA 1155 RAM Recommendations

[cts6288]

I recently have decided to upgrade my system and am strongly considering an i7-2600k which seems to be the best bang for the buck. So I went from there and found a motherboard that fits what I need which I presume would be the:

ASUS P8Z68-V LX LGA 1155.
http://tinyurl.com/7zwlcvn


I then looked up the manual for the memory specs and found that this motherboard works with 1600 / 1866 / 2133 / 2400 however it says on page 2-14 under 2.4.4:

"Selecting a very high frequency may cause the system to become unstable! If this happens, revert to the default setting."

Manual (5MB)
http://tinyurl.com/6uobhtr


Now does this mean that overclocking memory to a higher frequency would be unstable or the overall use of higher frequency memory rated as 2133 or 2400 just be unstable all together? My thinking is one of these:


2133
http://tinyurl.com/7ok9tk3
$35x2


1866
http://tinyurl.com/7ld4msh
$75x1


1600
http://tinyurl.com/3czn6fc
$50x1


Only G.Skill makes DDR3-2400 in 2GBx4 modules for $325 so I’m not going that high. I’ll hunt down the 2133 if concurred that this should be a reasonable stable purchase with my motherboard.

Also, I've always been a Crucial fan but I see that Corsair has some good reviews...any recommendations? I do not plan on overclocking whatever it is I purchase.

A little off topic, but ASUS is recommended for Intel chips as well right? I've always had AMD/ASUS combos and love them but just wondering since I'm already posting here the thoughts on an Intel/ASUS combo. Thank you!

 

[geofelt]

To answer some of your questions:

The current Intel nehalem and sandy bridge cpu's have an excellent integrated ram controller. It is able to keep the cpu fed with data from any speed ram.
The difference in real application performance or FPS between the fastest and slowest ram is on the order of 1-3%.

Synthetic benchmark differences will be impressive, but are largely irrelevant in the real world.

Fancy heat spreaders are mostly marketing too.

Only if you are seeking record level overclocks should you consider faster ram or better latencies.
Read this Anandtech article on memory scaling:
http://www.anandtech.com/show/4503/sandy-bridge-memory-scaling-choosing-the-best-ddr3/1
---------------bottom line------------

DDR3 1600 is the sweet spot.

You want documented ram compatibility. If you should ever have a problem, you want supported ram.
Otherwise, you risk a finger pointing battle between the ram and motherboard support sites, claiming "not my problem".
One place to check is your motherboards web site.
Look for the ram QVL list. It lists all of the ram kits that have been tested with that particular motherboard.
Sometimes the QVL list is not updated after the motherboard is released.
For more current info, go to a ram vendor's web site and access their ram selection configurator.
Enter your motherboard, and you will get a list of compatible ram kits.
While today's motherboards are more tolerant of different ram, it makes sense to buy ram that is known to work and is supported.

ASUS motherboards are good, regardless if they are for Intel or AMD.

If your use is for multi threaded production apps, then the 2600K is as good as it gets. The "K" lets you overclock with a Z68 motherboard, and it is a painless boost from 3.4 to 4.0-4.5.

If your use is for gaming, then the 2500K is a better buy. The extra hyperthreads are largely useless when games do not usually use more than two or three cores. The $100 saved is better spent to get a better graphics card.

 

[cts6288]

The difference in real application performance or FPS between the fastest and slowest ram is on the order of 1-3%.
...
DDR3 1600 is the sweet spot.

So then getting the 2x4GB of DDR3-2133 for $70 then really isn't a good idea...even if only a few bucks more.

RAM UPDATE: I did some further reading and I read that the CAS Latency plays an important role as well, and pricing shows that as a factor too. The DDR3-2133 is a CAS 9 whereas:

Corsair DDR3-1600 CAS 7
http://tinyurl.com/6thcvxh

My gut is on the 1600 due to A) geofelt's recommendation above , B) ASUS' stability note listed above , and C) the CAS Latency difference from 9 to 7. Please confirm that I'm on the correct path.

If your use is for multi threaded production apps, then the 2600K is as good as it gets. The "K" lets you overclock with a Z68 motherboard, and it is a painless boost from 3.4 to 4.0-4.5.

If your use is for gaming, then the 2500K is a better buy. The extra hyperthreads are largely useless when games do not usually use more than two or three cores. The $100 saved is better spent to get a better graphics card.

The high end use will be gaming however it will be used for web design, Photoshop, and the usual apps. I already have the video card:

XFX HD6970
http://tinyurl.com/4rs3a4o

So I just figured I'd get a better cpu and with AMDs new processor out all I read are disappointing posts that AMD hasn't touched 32nm like Intel has.

Here is a comparison between the i5 2500k and the i7 2600k:
http://tinyurl.com/73ca6ax

The difference I see is the L3 cache, but with games wouldn't they eventually make use of this technology so in the long term it would be a good investment?

CPU UPDATE: I did some more reading and then looked back at your post where you pointed it out but I missed it about the apps. The 2600k works better with multitasking where gaming doesn't exactly use it, or at least not yet. I may stick with the 2600k just because I don't want to have to deal with an upgrade down the road...if I have near best and it doesn't work then I know i have what I have without blowing near $500 whereas if I got the i5 (just the term i5 nerves me when an i7 is available) and it is slow then I'll wonder if my purchase was wise if only a $100 more was needed. Your thoughts?

 

[geofelt]

On a high end build, $100 does not mean that much, If your budget is not a real problem, go ahead and getthe 2600K. I really don't think the next step, the 2700K is worth it. The "K" and a P67 or Z68 motherboard lets you overclock, and all chips will oc to about the same level if it is a conservative oc.

Higher speed ram is really normal ram that has been binned to select the better samples, and is capable of achieving higher speeds by overclocking it with higher voltage. On ram, lower latency is good, higher speed is good, but there seems to be a trade off, lower latency comes with slower speed ram.

Regardless, my take is more ram trumps faster ram. Since ram is cheap, why not get 16gb? 1600 ram is fine, even 1333 would be ok.
You will not be able to detect the difference in teal world apps without a synthetic benchmark.

 

[k1114]

I find it weird that you chose the cheapest lowest end asus z68 mobo on a high end build. Cheaper gigabyte and asrock mobos are better than the le or lx. http://www.bit-tech.net/hardware/memory/2011/01/11/the-best-memory-for-sandy-bridge/6 Here's a benchmark to support geofelt. It even shows 4gb vs 16gb but there is no difference. Fps differences are within the margin or error imo as the anandtech article shows random placement with fractions of fps. http://www.anandtech.com/show/4503/sandy-bridge-memory-scaling-choosing-the-best-ddr3/6

Edit: Btw off topic but you don't need to use tinyurl, the forum auto shortens long links anyways.