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memory choice & general questions

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July 13, 2007 1:17:57 AM

I'm trying to put together a new computer. I've thought of several possibilities, but all of them revolve around a C2D e6600 (maybe 6700) on one of these two motherboards: Asus P5W-DH Deluxe or Asus P5W64 WS Pro. I intend to overclock the CPU, but nothing extreme; just as much as a good air cooling solution allows me.

I'm finding it hard to decide which kind of RAM would be appropriate for this. First of all, for what I have been reading, I understand that RAM usually runs at the same frequency as the FSB. So, if for example I was to leave the CPU at its stock 266Mhz and my RAM was rated DDR2-800 (which means 400Mhz), it would be overkill, and only by reaching an FSB frequency of 400Mhz would I put my RAM to full use. Is that always true? If not, can anyone tell me of any situation where a FSB/RAM frequency rate different from 1 would be acceptable or desirable?

Secondly, if this is generally true and I keep equal frequencies for FSB and RAM, it means that as soon as I exceed a FSB speed of 400Mhz (something both of the mentioned motherboards allow), my DDR2-800 will be obviously overclocked. I'd rather not buy anything over DDR2-800, so the question is: how far can you generally push a RAM overclock before the system becomes unstable? I know it obviously depends of your choice of RAM. But say I wanted to reach an FSB frequency of 450Mhz, could I go with a Corsair XMS2 DDR2-800? Would it endure the extra 50Mhz without problems? And another question, does anyone know the difference between the Corsair XMS2 and the Corsair XMS2 CL4? By the way, when is it convenient to change the memory timings from their stock values to lower ones? Is there a really noticeable perfomance difference?

Regarding voltages, I'm quite lost too. Not only when it comes to memory, but in general. It seems that when you overclock, you should generally start increasing your voltages along with the frequencies. But how much? Is there a rule that tells you how much you should turn up each of the controllable voltages (FSB, Northbridge, memory, etc.) for a certain increase in FSB frequency? Can I tell beforehand what will be enough for my final overclock or am I condemned to trial and error? For what I've seen in the guides posted in the Overclocking section, when people reach an overclock they deem reasonable, they start lowering the voltages until stability problems appear. Why don't they leave them where they were? My guess is that voltage contributes directly to heat production and therefore it is desirable to keep it as low as possible as long as everything works fine, but I don't know if this is correct.

Now I think of it, some parts of this post could and should have been in Overclocking. Maybe I should post them there as well...

Thanks in advance :) 
July 13, 2007 9:57:12 AM

Well, judging from what people have to say about the Corsair XMS2 DDR2-667 (http://www.newegg.com/Product/Product.aspx?Item=N82E16820145015), I'm guessing that for my purposes a kit of Corsair XMS2 DDR2-800 would be enough. Maybe even overkill. Do you think I could go for something cheaper?

Another question. Is there a reason why a Corsair XMS2 DDR2-800 2x1 kit should cost me more (131€) than 2 separate 1Gb sticks (55€ each)? My guess is there's a difference in timings, but those aren't listed in the catalog, so... If that's the case, and one of them is rated 4-4-4-12 and the other 5-5-5-12, is the 20€ difference worth it? Because it seems you can generally set a decent 5-5-5-12 memory to 4-4-4-12 with no trouble. And even if you didn't, I don't know if that would make a noticeable difference.
July 14, 2007 12:29:29 AM

Likely, the 20EUR difference is not worth it, but don't count on being able to run 5-5-5 RAM at 4-4-4 "with no trouble".
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July 14, 2007 4:42:22 PM

gusanoapestoso said:
Because it seems you can generally set a decent 5-5-5-12 memory to 4-4-4-12 with no trouble. And even if you didn't, I don't know if that would make a noticeable difference.


Usually you can get sticks of ram with different timings to work together, but they will be limited to the timing of the slowest stick, in this case 5-5-5-12. Theat said, ram with different timings may have a conflict and refuse to work at all. Its pretty much of a guess and gamble to try such a thing.

Sticks of ram that are sold in bundles are matched together at the factory, so there is a guarentee they that will work together. If you buy then individually, even if they appear to be the same in the advertisments, they may have subtle revision differences which limit their ability to work together. They will work, but again, only at the speed of the lessor stick. That is the main explaination behind higher prices for matched pairs.
July 15, 2007 11:02:59 AM

That makes sense.

Now, another question. I had pretty much made up my mind to get 4Gb (4x1Gb, Corsair XMS2 DDR2-800), because some of the apps I use would probably benefit from them, and now seems to be a good moment for purchasing memory because of the low prices.

But that would leave me with two options, none too appealing. The first one, being stuck with 3 - 3.5Gb in Windows XP (seemingly depending on the amount of physical memory of the rest of my devices, the page file, and such things). Windows Vista, as a 32-bit OS, wouldn't help either. The second one, switching to Windows XP x64 or Vista 64-bit. But I've been reading some, and the compatibility issues of these two don't seem as minor as I had thought (for me, at least).

On the other hand, 4Gb will probably become a basic need for almost everyone not too far in the future, so I guess most people will eventually resort to Vista 64-bit to overcome the current lack of memory support. When that day comes, I'll be sitting pretty. I won't have to worry about finding RAM sticks that match mine, or... well, spending money on them.

So, what worries me the most is that some people tend to think that having 4 memory banks is not a great idea performance-wise, and I would be better off with 2x2Gb (which I can't afford at all right now). Do you know anything about this? Is it true?
July 15, 2007 2:35:00 PM

Ok, in some ways you're stuck between a rock and a hard place. As you say, whether XP or Vista 32, the OS will only address a little over 3 gig of ram. You can still get the 4 gig, but not all of it will be used. Tying into that is the question of 4x1 gig or 2x2 gig sticks. Using a 4x1 setup will limit you to 2T timing, while the 2x2 setup will allow 1T timing. At the same time, the 2x2 ram hasn't got good timing anyway at this moment, so the 4x1 set may work better, as well as being cheaper.

I've owned XP64 Pro and it has its good and bad points. It does offer 64 bit computing and the ability to use lots of ram. It is also quite stabile That's good. What's bad is that M$ pulled its support very quickly when the developement of Vista began. Further, at least in the beginning, a lot of hardware didn't work well with it, lack of drivers and such. That isn't so much of a problem now, as most companies have written 64 bit drivers for their hardware. Vista 64 has some problems, but really they are pretty much the same whether Vista is 32 bit or 64 bit. As to the compatibility problems you have in your machine, that's where major overhauls sometimes need to be done.

If I was to buy a new OS, I'd go for the Vista 64, mainly because that's where the future lies. In the meantime, getting the 4 gig of ram sets you up nicely for that future. I should note that's the future, not the present. Right now, nothing requires 4 gig of ram, no matter what OS you're using. A year or two and the 4 gig will probably be needed, but that's then. If you are pressed for money, I'd suggest buying only 2 gig of ram at the moment and then upgrading other hardware to be Vista compliant. Then in the future, you might buy a set of 2x2 ram, when it probably will have dropped in price and increased in performance. That's only a suggestion, what I would do if short on money.
July 15, 2007 5:22:43 PM

Thanks a lot for your reply.

When I was talking about compatibility before, I didn't mean hardware issues in Vista 64 or XP 64, since I'm building my computer from scratch. I meant I'm not completely sure whether some of the apps I intend to use currently work well (or even work, period) on any of those operating systems. For example, Alias Studio is troublesome, but it's not certain if it's due to poor 64-bit GPU drivers, or if deeper causes exist.

The reason why I thought I should get 4Gb now is that I may start putting them to good use right away, because some of the tasks this system will be performing are truly memory-intensive. Also, considering that in a year or two those will be actually needed, and memory has reasonable prices at the moment, it's not really a waste of money. Finally, I feel that video cards are the fastest-aging hardware, and therefore it might be a good idea to save 100€ by getting a moderately powerful DX9 card (like a X1950XT) instead of a half-baked DX10 card with a great DX9 performance (like a 8800GTS), use them to buy the memory now, and hope for a video card upgrade in the future, instead of the memory upgrade you mentioned.

By the way... when you talk about buying a set of 2x2 sticks in the future, would that imply scrapping the 2x1 I would have? Would it cause stability issues to have 2x2 + 2x1 = 6Gb (provided I can find memory with the same speed and timings)?
July 15, 2007 7:52:06 PM

I guess I misunderstood what you meant by compatibility problems. Since its software related, then that will probably be worked out during the next year. Most software problems I've run across so far have been driver related, so with rewrites of the software, things should get better. Troublesome hardware is another thing. My X-FI card, for example, seems to have some hardware issues that will take a totally new card to fix. Maybe not, but that's what it looks like at the moment. Because of the current problems I have with my X-FI in my Vista computer, I use the card in a second computer and just use the on-board sound with Vista.

If you can use the 4 gig of ram right now, then buy it. The penalty from running 2T instead of 1T affects games more than office apps. You may be right about the video card, though that's a bit of a personal choice. Until and unless you run DX10 games, then a DX9 card such as an X1950 will suffice. I do have a 8800 GTS card and it helps a lot with the current DX9 games, but no one really knows what it will do with DX10 games. Might be good, might not. I had to replace a burned out card anyway, so I went for the 8800 instead of a X1950, but that's a personal choice and nothing else.

Few motherboards support 6 sticks of ram, so what I meant was to buy the 2 gig now and then replace it with 4 gig later. I've done similar in the past with starting with 1 gig in 2x512 mb setup and then replacing it with a 2x1 gig set at less cost then the original 2x512 mb setup. Yes, that means scraping the original ram sticks or selling them, which seems wasteful, but it can be cheaper in the end. In my case, I used the old ram in a computer for my son, so it wasn't wasted. In any case, if you have use for 4 gig now, then buy it now.
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