Lower CAS worth the price?

[Gh0s7y]

Hello,

I am on the verge of buying new components for my PC, this includes RAM.
Now I heard from some people lower CAS latency really is worth is, but I don't seem to be able to find why.
Otherwise would it be good to take more MHz instead?

Here's a little list of stuff I'm getting:
- i5 2500K
- GA-Z68X-UD3P-B3 (or GA-Z68XP-UD3P if possible)
- G.Skill Ripjaws F3-10666CL7D-8GBXH

Now CL7 1333 costs more than CL9 1600, so again, what would be wise?
Now I'm not a rich guy and quite low on money at the moment, so every cent less the better, however because of two experienced friends saying you'll be getting fast loading times etc. with lower CAS, I'm not sure what to take. Is the lower CAS even noticable? I also heard 1600MHz or higher doesn't help a thing with i5, any clarification on this would be nice as well

Please help me out on this

Thanks in advance

Ghosty

 

[buzznut]

You'll notice more responsiveness with an SSD. The latency won't matter much, a few frames per second on benchmarks mostly. I would go with the less expensive ram, 8gb is a pretty good deal right now. I'm running some DDR3 1600 Mushkin memory that I'm very happy with, CL 9 on those. The PH II that I'm running only has a 1333Mhz controller, so I've got them OC to 1600 with the correct timings, but I had to change the timings in the BIOS because they went to CL 10 when I bumped up the speed.

At any rate, if you're a hard core enthusiast and want the fastest speeds available then the CL 7 may be worth it to you. But I wouldn't go down to 1333Mhz ram for just that.

 

[Gh0s7y]

Thanks for your reply buzznut

Well okay so lower CAS is only noticable in benchmarks and not in practice.
However you didn't answer my question if 1600 is also noticably better than 1333 on i5. Same issue here from two different friends, they both told me you wouldn't notice the difference between 1333 and 1600 MHz. If anyone can clarify that for me, I would be a happy man

 

[buzznut]

Thanks for your reply buzznut

Well okay so lower CAS is only noticable in benchmarks and not in practice.
However you didn't answer my question if 1600 is also noticably better than 1333 on i5. Same issue here from two different friends, they both told me you wouldn't notice the difference between 1333 and 1600 MHz. If anyone can clarify that for me, I would be a happy man

Noticeable? In terms of system responsiveness, I don't think you could tangibly tell the difference between a system running 1333Mhz and the same one with 1600. There would be a slight difference in benchmarks certainly but I doubt anyone would notice the minor bump in speed. Not like going from 2 gigs to 4 gigs, which in WIN7 is quite a difference.

 

[Gh0s7y]

Noticeable? In terms of system responsiveness, I don't think you could tangibly tell the difference between a system running 1333Mhz and the same one with 1600. There would be a slight difference in benchmarks certainly but I doubt anyone would notice the minor bump in speed. Not like going from 2 gigs to 4 gigs, which in WIN7 is quite a difference.

Alright thanks then I'll take 1333

Then I think I'll take this one, it's 1,5V as it wants and the cheapest RAM that has heat spreaders (in my country at least).
G.Skill Sniper F3-10666CL9D-8GBSR2

 

[jemm]

Think about 2 memory kits both at the same speed, be it 1333Mhz or whatever, but with different latencies values. Lets say a 1333Mhz kit, one CAS7 and another CAS9. Obviously the low latency kit is better.

As for the kits runing at 1600MHz they are really intented for overclockers, despite of its CAS. However some enthusiasts see some performance gain while gaming at 1600MHz or higher speeds.

If are about to get a 1333Mhz, then why not get a low latency kit, lets says CAS7 or CAS8? The kit you linked is CAS9.

 

[Gh0s7y]

Indeed, that is because CL7 with 1333 costs more than 1600 MHz here.

And I am intending to overclock (obviously since the CPU is unlocked ), so then the higher Hz the better?

 

[jemm]

If you are willing to overclock, then yes, as you might have to downclock your memory speed.

 

[Gh0s7y]

That would mean that if I overclock using 1333 MHz RAM, it will end up as 1200 MHz or something?
Now I'm rather new to overclocking so I don't know a lot of stuff about it.

 

[Zenthar]

The difference will be minimal. CAS latency is expresses in cycles, not in any unit of time so even if the DDR3-1600 has a higher CAS, each cycle being shorter makes up most of the difference. As a rule of thumb to compare "speeds", I just do CAS/MHZ (7/1333 = ~0.00525 and 9/1600 = 0.005625), the lower the better. But as most people said, a 10% difference in theoretical speed doesn't mean the PC will be 10% slower as there a lots of other bottlenecks.

 

[jsrudd]

If you want to overclock go with the 1600mhz RAM. It will give you some more headroom.

The memory has to be set as a multiplier of the bclock. So, depending on your memory, might have a choice between a 7 and 8 multiplier. One would put you at 1200 and the other at 1400. You would have to choose the 1200 or overclock your RAM. Of course, the same is true with 1600, but you're choosing above or below 1600 instead of 1333.

 

[Gh0s7y]

The difference will be minimal. CAS latency is expresses in cycles, not in any unit of time so even if the DDR3-1600 has a higher CAS, each cycle being shorter makes up most of the difference. As a rule of thumb to compare "speeds", I just do CAS/MHZ (7/1333 = ~0.00525 and 9/1600 = 0.005625), the lower the better. But as most people said, a 10% difference in theoretical speed doesn't mean the PC will be 10% slower as there a lots of other bottlenecks.

Thanks, this clarified a lot for me

If you want to overclock go with the 1600mhz RAM. It will give you some more headroom.

The memory has to be set as a multiplier of the bclock. So, depending on your memory, might have a choice between a 7 and 8 multiplier. One would put you at 1200 and the other at 1400. You would have to choose the 1200 or overclock your RAM. Of course, the same is true with 1600, but you're choosing above or below 1600 instead of 1333.

So it is as I thought
When taking the memory I previously suggested, I could be able to overclock it wouldn't I? I mean it does have heat spreaders...
Anybody having experience with that or comparable memory?

Otherwise, could anyone advice me some quality but cheap-ish memory?

 

[jemm]

Try CORSAIR Vengeance 8GB (2 x 4GB) http://www.newegg.com/Product/Product.aspx?Item=N82E16820233144

 

[k1114]

If you want to overclock go with the 1600mhz RAM. It will give you some more headroom.

The memory has to be set as a multiplier of the bclock. So, depending on your memory, might have a choice between a 7 and 8 multiplier. One would put you at 1200 and the other at 1400. You would have to choose the 1200 or overclock your RAM. Of course, the same is true with 1600, but you're choosing above or below 1600 instead of 1333.

This is wrong, SB does not overclock like other systems and changing bclk is not recommended. You can but only by about 5% before it's unstable (100 to 105) and it is not recommended as it's linked to pcie, sata, etc. so can cause corruption. Ram and cpu overclock are completely separate although the ram controller is integrated on the cpu with other northbridge functions, so only the voltage is the only concern. Heat spreaders are irrelevant at 1.5v, it's just for looks as the ram doesn't create much heat at this voltage.

Here's some articles about sb and ram. 1333 and 1600 are usually only $2-5 difference so would still recommend 1600 if it's that small of a price difference.
http://www.bit-tech.net/hardware/memory/2011/01/11/the-best-memory-for-sandy-bridge/
http://www.anandtech.com/show/4503/sandy-bridge-memory-scaling-choosing-the-best-ddr3

 

[Gh0s7y]

This is wrong, SB does not overclock like other systems and changing bclk is not recommended. You can but only by about 5% before it's unstable (100 to 105) and it is not recommended as it's linked to pcie, sata, etc. so can cause corruption. Ram and cpu overclock are completely separate although the ram controller is integrated on the cpu with other northbridge functions, so only the voltage is the only concern. Heat spreaders are irrelevant at 1.5v, it's just for looks as the ram doesn't create much heat at this voltage.

Here's some articles about sb and ram. 1333 and 1600 are usually only $2-5 difference so would still recommend 1600 if it's that small of a price difference.
http://www.bit-tech.net/hardware/memory/2011/01/11/the-best-memory-for-sandy-bridge/
http://www.anandtech.com/show/4503/sandy-bridge-memory-scaling-choosing-the-best-ddr3

Thanks a lot for those links k1114 !
I found the benchmarks and info very helpful, especially the first one.
Well now I know I'm going to take 1600MHz after all, and I don't really care anymore about CAS
And also about the heat spreaders, I guess I'll take ''normal'' memory without the heat spreaders then to save some more money

One of the cheapest in my country is this one: Corsair Vengeance CML8GX3M2A1600C9, being sold for 38 euro's, which is almost 50 dollars. Good choice or..? Also I've been wondering what the B means in Corsairs product types, does it mean "Blue" or is it actually different aside from the color
AND why are Corsair modules WITH heat spreaders cheaper than without? o.o

Thanks everyone so far for their contribution to this topic ^^ it all helped

 

[k1114]

Can you post a link? Is it the vengeance with high heatsinks or is it the low profile ones? Because the high ones will get in the way of most aftermarket cpu coolers. The B is the color since corsair has the same exact kits with different colors to match your system or whatever. The reason the ones with heat spreaders are cheaper is probably old supply as ram prices have dropped a lot and most everyone buys the ones with heat spreaders.

 

[Gh0s7y]

Can you post a link? Is it the vengeance with high heatsinks or is it the low profile ones? Because the high ones will get in the way of most aftermarket cpu coolers. The B is the color since corsair has the same exact kits with different colors to match your system or whatever. The reason the ones with heat spreaders are cheaper is probably old supply as ram prices have dropped a lot and most everyone buys the ones with heat spreaders.

It is the low profile one: <link (dutch)> | <link (official)>

 

[k1114]

OK then they're good.

 

[Gh0s7y]

Well, that's all I wanted to know =P

Thanks everyone

*closes topic*
*finds out he can't do that*