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What DDR2 memory speed is recommended for Conroe?

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May 30, 2006 7:35:48 PM

I'm running a AMD Athlon 64 3500+ S939 CPU right now and I'm thinking of upgrade to either a Intel Conroe or possibly one of the faster AMD AM2 CPU's. Since it's a bit too much of money for me to buy all at once at the same month I was thinking of already now ordering the DDR2 memory so I'll "only" have the mobo and cpu left to buy once they're released.

I'm planning on buying 2 gigs of DDR2-800 Mhz from Corsair. Is there anyone who knows if this will be enough for Conroe? I know 667 Mhz is enough for an AM2.

Didn't know if I was going to post this in the CPU or Memory part of the forum. Hope I did the right thing. Anyways any help is appriciated.
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June 2, 2006 3:16:18 AM

I'm going to tell you something very unpopular with the 13-year-old idiots that push this stuff: The speed of the memory you choose won't matter "much".

Intel is talking about 1066 and possibly as high as 1333 bus for the Conroe. First of all, let me just make sure everyone reading this knows that it's a 64-BIT BUS, so that DDR2-667 in dual channel mode has the same bandwidth as a "1333MHz bus".

What's going to matter most is a balance between data rate and latency. You'll probably find ideal performance in that newer PC2-6400 CAS4 (SuperTalent), it's better memory than the Corsair PC2-6400 CAS3 (which really runs 3-4-3 rather than 3-3-3) because it doesn't require added voltage to get to its full rated speed.

Feel free to try the PC2-6400 CAS3 if you like :p 
June 2, 2006 3:21:46 AM

I believe the highest memory the chipsets support is DDR2 667.
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June 2, 2006 5:17:43 AM

The 775Xsupports a 1:2 CPU:D RAM ratio, but some boards don't.

1:2 works to make a P4 with 800 bus use DDR2-800 at full speed, and a P4 with 1066 bus work with DDR2-1066 at full speed, the actual clock rate being CPU:D RAM at 200:400 and 266:533 respectively.

The same applies to Core2's of course, it's all in the motherboard/chipset. I know the Foxconn 775X7AA doesn't do 1:2, but I'm fairly certain the rest do.

The Foxconn board can do DDR2-667 with an 800 bus CPU, or DDR2-800 with a 1066 bus CPU, as its limits. I believe most others go all the way.
June 2, 2006 5:19:08 AM

Ah ok, thanks. 8)
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June 2, 2006 5:58:56 AM

Yes, well, I have the SuperTalent PC2-6400 (DDR2-800), it runs 4-3-4-8 and 800 data rate using only 1.8v. And the fact that it does those impressive timings at 1.8v means it's not overclocked, unlike Corsair or worse, OCZ requiring as much as 2.1v just to get the rated speed.
June 2, 2006 1:16:30 PM

Ok, that sounds good :)  I knew I thought the DDR2-1066 sounded like overkill just by thinking about it :p  Glad I wouldn't have to buy such insanely costly type of memory.

Anyways, I live in Sweden, and I think Crucial, Corsair or Kingston is the easiest memory for me to buy. Is there any particular memory speed and brand that is most recommended, that has better features, best speed, and especially important, something that I could buy that would make sure I wouldn't have to run the memory bus and FSB bus asynchronous.

Also, if I understand correctly, you're actually saying that even with the upcoming 1333 FSB Conroes, that DDR2-667 is the optimal performance that you will get and any higher speed memory than that won't improve anything but rather eventually cause troubles such as asyncronous fsb and memory bus?
June 2, 2006 1:34:23 PM

Crucial Ballistix do wath U want, goes by side with FSB 8)
For others i dont know :cry:  (money,money,money,must be funny...)
June 2, 2006 1:50:54 PM

Well with DDR2 and video cards dropping in prices like lead balloon Id purchase those items last.
The new AM2 cpu's and motherboards wont drop in price for some time. Id buy those first, especially the mobo.
As far as Intel processors and mobo's, same deal, they are already about as low as they go.
June 2, 2006 2:59:00 PM

I will go with Conroe if the performance lives up to the "hype". Otherwise the 4800+ X2 AM2 is really the only CPU that'll really boost the performance from my current single core 3500+ in my opinion. I must say I'm a bit skeptical to AM2 after all, especially reading all about that some of the CPU's actually don't even run at 667 FSB. And I can't really like AMD's new system of going up and down in cache while still the rating only goes up. Believe me, I'm not a fanboy or anything I just think that Intel looks to be the best deal for the rest of the year if not longer. But let's leave that final statement until Conroe official benches are up :) 

Yeah I could buy the DDR2 memory last. But I'd really like to have a complete Conroe system by end of July or beginning of August. If all goes right with performance and availability of course. But if I understand right, you have to have the right mobo with which you could choose the right memory to run synchronously with the FSB, meaning if I buy a pair of DDR2-667 for example, with the 1066FSB Conroe, that I definitely can run them att 533 MHz x 2 -> 1066 Mhz FSB?

I know now it starts to sound like overkill but with the 1333FSB coming up you would want faster memory that wouldn't have to replaced again, memory that you could use for one to two years or so.
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June 2, 2006 5:40:53 PM

DDR2-667 in dual channel mode has the same bandwidth as the eventual 1333 bus, but you'd really need tight timings to get top performance. In that case DDR2-667 CAS3 would provide similar performance to DDR2-800 CAS4 and DDR2-1000 CAS5, where the CPU bus is still the limitting factor.

AMD's CPU bus is internal, I like the idead of putting DDR2-800 on AM2 even if it's not "needed".
June 9, 2006 1:08:18 AM

CORSAIR XMS2 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800
(PC2 6400)
Unbuffered Dual Channel Kit System Memory Model TWIN2X2048-6400C3

Cas Latency: 3
Features: EPP (Enhanced Performance Profiles)
Heat Spreader: Yes

Timing: 3-4-3-9

If the motherboard is not using the NVIDIA chipset - Does
this timing hold true? I'm planning on getting the ATI's 3200 express
chipset, it the reviews look great.
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June 9, 2006 2:44:02 AM

"Overclocked" RAM will default to lower settings, EPP is meant to be a workaround. For non EPP enabled boards, you have to make the settings manually. EPP is only a method to allow manual settings to be made automatically, nothing more than a time-savings feature.
June 9, 2006 3:35:07 AM

Thanks. Will the advertised timing of 3-4-3-9 be the default settings?
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June 9, 2006 4:11:44 AM

RTFM, last I looked they published the default SPD values in their pdf file on the RAM.

Probably defaults to something like 4-4-4-12 and requires manual adjustment to get 3-4-3-9 unless your board supports the EPP function, in which case it will make the custom settings automatically.
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June 9, 2006 4:13:44 AM

I should also note that the reason for this is that the memory requires custom voltage for the enhanced timings, and EPP stores both where you'd otherwise set both timings and voltage manually.
July 5, 2006 7:56:44 PM

While 3-3-3-3-12 DDR2-667 will be fine for a Conroe at stock speeds, what about overclocking?
I'll be buying a 6600 and aiming to get it to 4GHz at least with water-cooling. That means an FSB nearing 450MHz, so would I be better-off with 5-5-5-5-15 DDR2-800? (I'm not breaking the bank to pay for RAM, so those are my options.) Might be able to stretch to 4-4-4-5-15 DDR2-800, but how much improvement would I see?
July 5, 2006 9:00:36 PM

is it possible to put PC8500 with conroe, but put the speed to 800mhz, that will allow 200mhz room for overclocking?
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July 5, 2006 9:04:37 PM

DDR2-533 is SYNCHRONOUS for the 1066MHz Conroe bus, using dual channel mode. So DDR2-667 would be fine for overclocking, just choose the lower ratio (533) and push it up from there.
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July 5, 2006 9:05:08 PM

PC2-8500 will run any speed you want below its rated speed.
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July 5, 2006 9:30:57 PM

I just hope that the CORSAIR XMS2 2GB DDR2 800 CAS 4 RAM will be good enough for my purposes. Not sure if I will be overclocking though. I plan on using a Scythe Ninja to cool it passively (without the fan) so that I can have a quiet system.

BTW, how good are Patriot's RAM? These Patriots RAM sticks are also CAS 4 with similar timings as the Corsairs above and they are $70 cheaper after a rebate. I've only used Corsair and Crucial RAM.
July 5, 2006 9:54:26 PM

Maybe I'm missing something (the last serious overclock I did was on a Celeron 300A).

At stock speed the FSB base frequency is 266MHz, giving a quad-pumped FSB of 1066MHz and a synchronous DDR2 speed of 533MHz, as you said. But if I manage to raise the base to overclock to 450MHz, the synchronous DDR2 speed becomes 900MHz. At that point DDR2-800 would be running below the FSB rate (which I'd have to live with, as I'm not forking out for the expensive stuff). Is that right?
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July 5, 2006 11:41:51 PM

You really think you're going to take it from 266 to 450? Wow. Let's see, for a 2.13GHz processor that's 3.6GHz. OK, so maybe you can!

I'll let you know what my two favorite sets of modules are: I have some Corsair TWIN2X2048-5400C4 that is capable of 880MHz, and I love it because it's cheap. And I have some SuperTalent PC2-6400 that runs up to 960MHz (maybe higher on better equipment), I love it because it runs at 800MHz CAS 4 using the standard 1.8v...so it's real actual PC2-6400, not overclocked PC2-5400.
July 6, 2006 1:34:09 PM

Quote:
You really think you're going to take it from 266 to 450? Wow. Let's see, for a 2.13GHz processor that's 3.6GHz. OK, so maybe you can!


Well, E6600 at 4GHz on air-cooling, so I should have a good chance of getting it stable at that speed (or perhaps 3.9GHz and a lower vcore) with water-cooling.
Anonymous
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July 6, 2006 4:14:16 PM

The way I see it, you get a 6600 like the one from xtremsys, you shove some ultra tight timming DDR2 800 in it, and run it 1:1 @ 3.6 ghz.

Thats a 50% overclock, will result in really high bandwith and should annhihilate any non-OCed CPu out there(to be expected).

I beleive on the preliminary data, that such a setup on water cooling, super good air might be possible for 24/7 use. You will need solid motherboard thought. Maybe I'm a bit optimistic, but thats the system I'll be shooting for in September.
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