Sign in with
Sign up | Sign in
Your question

Choosing memory for Core i7

Last response: in Memory
Share
August 4, 2009 3:49:32 PM

Hi,

I'm thinking about getting a core i7 system and already did some research on which components I should get. I already decided on the CPU and motherboard. These will be an Intel Core i7 920 and a Gigabyte X58-UD5 mobo. Now I only need some good and fast RAM.
In the shop where I am used to buy my PC components, I can get OCZ Platinum PC3-16000 (2000MHz) 6GB for a very low price at the moment. I don't know how long it will stay at that price so I'd like to decide fast.

Now the advice I'm asking, is it wise to choose RAM with such a high speed? Maybe problems can occur with some of the various multipliers there are in core i7 setups, causing instability? I can tell you that I'm planning to do a higher OC on my CPU, taking it up to around 3.4 GHz (should be possible I think). This requires a baseclock of 170MHz at the locked CPU MP of 20. Can I play around with the memory MP to get it running at +/- 2000MHz with that BCLK? BTW I also heard that the mem. MP should always be at least half the Uncore or QPI Multiplier (not sure which of both it is). Might I run in some problems here?

Any advice is always welcome, as well as recommendations on other memory kits,

Thanks anyway

More about : choosing memory core

August 4, 2009 3:59:01 PM

The memory itself should not cause issues, but I wouldn't spend a lot extra on it since testing has consistently shown higher memory speeds have less impact than tighter timings. Whether or not you can get to the rated speed is an issue nobody can answer since it will depend on your chip/mb/memory combo and how they interact. I would concentrate on lowering my timings before trying to get up to the top speed though....and if you can get some good 1600mhz memory for substantially less that has better timings I would go that route instead. I really don't think its worth spending over $100 on a 6gb kit right now. I've yet to see any over that price that actually improve performance.
August 4, 2009 4:45:46 PM

Thanks for the reply.

As I already mentioned I can get that kit at a very low price, something I've never seen before. It's even cheaper than a 6GB 1600MHz kit with about the same timings!! I think the price must be mistake, but I 'm sure they wont say anything about if I buy it.

I know that you are right on the thing that lower timings are better than high freq. on a LGA775 system. But Core i7 is different I think. It has way more bandwidth on the memory bus than previous chipsets, so ultra fast RAM kits can live up to those speeds. Something that wasn't possible before.
However that's wath I have read about it, so feel free to reply


Related resources
August 4, 2009 4:57:53 PM

here you go...Anandtech also did a similar article with test up to 2000mhz and reached the same conclusions.
http://www.tomshardware.com/reviews/memory-scaling-i7,2...

With that being said, it is very possible if you can get it at the same price, you can tighten the timings at lower speeds even more on the 2000mhz, so if you can get it cheap enough it may still be worth it.
August 4, 2009 5:27:28 PM

Thanks a lot to link that guide. It shows indeed that even on Core i7 lower timings are better than higher speeds.

You also mentioned a very nice idea. I can buy that 2000mhz kit and run it @ 1600 with very low timings. I checked different RAM brands out and found out that the lowest out-of-the-box timings for 1600mhz were 7-7-7-20. That was a Corsair RAM kit. Do you think it is possible to reach these timings too on the OCZ kit if I lower the speed to 1600mhz?
August 4, 2009 5:47:10 PM

Yes, potentially even lower. In order to get the higher speeds timings have to be loosened, so the reverse of that is lower speeds and tighter timings. Of course, every overclock is different, so you might not get ideal results, but you are starting ahead of the game if you can get faster ram at the same price. It gives you extra room to play a little.
August 4, 2009 6:07:36 PM

Yes ideed. Like that I have the best of both worlds. I can run it @ 1600 with super low timings and if I want to check out extreme speeds, no problem at all. BTW, it might be even possible to lower the timings a bit even @ 2000. Right now they run @9-9-9-30. Maybe I can get it to 8-8-8-30 or something like that. Anyway, I can see that later.

However there is something else I don't get so well about RAM on Core i7. Intel says that 1.65v is the max or otherwise you risk damaging chipset/CPU/mem controller. However, take a lot at some higher speed DDR3 modules and practically all of them run @1.65v stock. That means there is little to no headroom for OC'ing or tightening timings without risking your setup. Is that normal?
August 4, 2009 6:14:24 PM

Don't confuse timings with voltage. Leave the voltage @1.65, but you can still mess with the other parameters.
August 4, 2009 6:22:26 PM

Allright. I wasn't planning to oc the ram however. Just a little bit curious.

Further, i guess it's a waste of money to buy XMP memory?
August 4, 2009 6:38:29 PM

You are asking the wrong guy...right now my motto is "nothing over $100 for 6gb" until someone can prove to me it really makes a difference that is worth the price.
August 4, 2009 6:52:54 PM

I live in europe and if you would convert the prices here from euro to US dollar with the current currencies, you would be well above 100$, but that's typically for this region. The US is paradise on earth to buy computer stuff if you ask me.

I'll give you some examples:

I can get that 2000mhz kit for 115€ which is about 165.50$
The lowest price I can get for that 7-7-7-20 Corsair kit is 130€ - 187$

So relatively spoken, the 2000mhz ocz kit is a very interesting deal, isn't?
August 4, 2009 6:58:53 PM

ouch!...yeah, I'm spoiled by the OCZ kits for $80 with low timings. Everytime newegg has a sale I load up...but I'm a system builder so I can never have too many cheap parts. I was wondering...in countries where parts are so high why don't more of you buy from system builders in the US? Even with shipping a high end system would have to be cheaper when all the parts cost over twice as much.
August 4, 2009 7:18:03 PM

I already considered buying my new pc in the US and then ship it over, but if something breaks down I have to send it all the way back and that's less interesting. Ofcoarse you can always send it back to the manufacturer instead of the shop, but I have never done that before and I'm a little bit afraid something can go wrong then. Not all manufacturers offer the same quality of support.

Right now I like the splendid service I get in my trusted shop and I can tell you, the prices I mention are about the lowest you can get here. If would tell a local expert about such quality components for these prices and he wouldn't know about it, he would not believ his ears (in the positive way then).
This is just the way modern technology is prices here and it isn't just pc components. Its also plasma tv's, blu-ray players, home cinema systems and so on. We're use to live with it so it isn't such a chock for me as it is for you.

But anyway, if you compare the prices and specs of both kits, which of both would you get?

I can also get the OCZ platinum 6gb 1600mhz 7-7-7-24 for 105€ (I won't show the $-prices anymore if they are too scary :)  ) That's one intersting kit too, maybe?
August 4, 2009 7:29:50 PM

for the difference of 10euros I would go with the 2000mhz also...it might not make that much of difference, but as we've discussed it will be fun to try, and future support might actually come along and make a real difference.
August 4, 2009 7:40:31 PM

Alright, I'll think about it but that's probably what I'm gonna buy too.

Thanks a lot for all the help. I really know a lot more about RAM now.

See you on the forums!
!