Corsair 2GB PC2-6400 C3 DDR2 Memory Review

[Apoptosis]

Corsair 2GB PC2-6400 C3 DDR2 Memory Review

With Intel Conroe systems coming to market and AMD's AM2 platform already available the need for enthusiast DDR2 memory has never been greater. Today we take a look at Corsair's PC2-6400C3 memory line, which is aimed at overclockers and gamers. The Twin2X2048-6400C3 comes with Enhanced Performance Profiles (EPP) and tight timings of 3-4-3-9.

After reviewing ten enthusiast brand lines from eight companies I feel confident to call Corsair's PC2-6400C3 memory line the ultimate enthusiast memory on the market today. Thanks to ability to run super tight CL3 timings up over 880MHz and CL4 timings well over 1.1GHz these modules will give gamers and overclockers ample room to best optimize their system performance. Corsair made the smart move to use Micron D9 IC's on their PC2-6400C3 modules and thanks to super tight screening they are able to produce these kits in volume...

Article Title: Corsair 2GB PC2-6400 C3 DDR2 Memory Review
Article Link: http://legitreviews.com/article/364/1/
Pricing Link: http://www.zipzoomfly.com/jsp/ProductDe ... de=85025-7
DIGG It: http://digg.com/hardware/Corsair_2GB_PC ... ory_Review

[infinitevalence]

Yeah these things get my vote as well i have seen some amazing results from other people who have used this memory. Funds permiting these will be going into my Conroe rig.

[=LAS=Spitfire]

Nice dude. How much does that kit run? Sounds like it would put a pretty nice dent in my wallet

[Apoptosis]

The kit runs $452 and as of right now both Newegg and Zipzoomfly are sold out.

[Ewart]

..Thanks to ability to run super tight CL3 timings up over 880MHz and CL4 timings well over 1.1GHz these modules will give gamers and overclockers ample room to best optimize their system performance. .

Great review thanks. I'm thinking of purchasing The corsair TWIN2X2048-6400 which is as far as I can tell exactly the same as the "Corsair XMS2 PC2-6400 Pro" reviewed, except I think the 'pro' edition has some LED's (although corsairs product brochure doesn't actually state this or hilight any differences what-so-ever)

Anyway, that aside my question is that the TWIN2X2048-6400 was evaulated in each test but not evaluated in the 'overclock' section. As I'm planning on getting an E6600 Conroe and overclocking it to 3+ Ghz, I'm wondering if this single test could be added.. or if somebody has spotted a review site that has done this, the info would be muchly apreciated

cheers

[Apoptosis]

Ewart,

Welcome to the forums... What overclocking timings would you like to see and I'll go run the tests for you on Corsair PC2-6400C3, C4, and C5 memory for you.

In terms of the differences between the modules I believe that roughly the top 6-8% of the IC's become PC2-6400C3 then the next 15% of IC's become PC2-8500 modules. The other 80% of the IC's tested become PC2-6400C4 and PC2-6400C5 modules depending on how they test out. A good number of IC's fail and never make it to any module series. If you are looking for the best overclocking modules then PC2-6400C3's are what you need. Corsair does a direct screen on each IC and sort them as needed. With roughly 7% of IC's meeting PC2-6400C3 standards it's clear why Newegg and Zipzoomfly are sold out of them. For every 300,000 Micron D9 IC's that Corsair buys only 21,000 can become 6400C3's. With each module using 8 IC's per side a 2GB kit comes with 32 IC's. Out of those 21,000 IC's that passed testing only 656 kits of PC2-6400C3 memory can be made. Then after making modules you get fall out again and screening errors, so that number of 656 is reduced even more. So with 300,000 IC's Corsair gets about ~600 2GB memory kits shipped...

Hope this helps as you are right by them being the same materials and build, but the IC's have passed different testing levels.

[Ewart]

Ewart,
Welcome to the forums... What overclocking timings would you like to see and I'll go run the tests for you on Corsair PC2-6400C3, C4, and C5 memory for you.

Wow that would be fantastic and real nice of you!! I was considering purchasing the (part#) "TWIN2X2048-6400" which I believe is the C5, as it is 30% cheaper than the C4. If it it won't run in an overclocked E6600 as I mentioned, I'd move up a grade to C4. As I need 4gb I'm a bit price sensitive! The C3 is simply out of the question in $NZ:

Corsair TWIN2X2048-6400 DDR2-800 Memory Kit - $470
Corsair TWIN2X2048-6400C4 DDR2-800 Memory Kit - $610
Corsair TWIN2X2048-6400PRO DDR2-800 Memory Kit - $690
Corsair TWIN2X2048-6400C3 DDR2-800 2GB Kit 3-4-3-9 - $1250

As I'm an overclocking amature I'm not sure of what 'timings' to ask for, my plan was to buy an E6600 and increase the FSB until I reached it's maximum stable speed. My understanding/assumptions -- is I need some reasonably good ram to do this as the RAM speed increases as the FSB increases?, so the RAM has to overclock to some degree? I'm not worried about the latencies being 5-5-5-12 as the relative speed increase seems minimal, less than 5%.

Given the reported overclockability of the E6600 and that
- the step up to E6700 (2.67ghj) is 70% more $$
- the step up to X6800 (2.93ghz) is 300% more $$

I think a lot of semi-knowledable people will just take the E6600 (2.4ghz) and overclock a 300 to 600mhz and put the money saved into RAM or something else.

[Apoptosis]

Ewart,

I'm not going to be able to get the benchmarking done tongiht and I'm going out of town tomorrow!

I'm posting an article tomorrow that looks at gaming performance on an E6600 processor versus an AMD 5000+, which will interest you.

[Ewart]

Ewart,

I'm not going to be able to get the benchmarking done tongiht and I'm going out of town tomorrow!

I'm posting an article tomorrow that looks at gaming performance on an E6600 processor versus an AMD 5000+, which will interest you.

No worries, enjoy your out of town trip, hopefully you can get a chance to checkout the C5 when your back. That E6600 article sounds interesting, will check it out. Cheers - Ewart.

[Ewart]

Ewart,

I'm not going to be able to get the benchmarking done tongiht and I'm going out of town tomorrow!

Not sure if your back yet; I've learnt some new info.. if my understanding is correct I do not even need to overclock the RAM in my planned scenario..


I saw something somewhere that implied the max CPU speed @ 1:1 is:

[DDR2 rate] / 2 * [CPU Multipler]

So DDR2-800 / 2: = 400
E6600 @ 2.4Ghz has a multiplier of 9.

So max speed without overclocking RAM is 9 * 400 = 3600mhz

perhaps someone knows if this is accurate? so in this case I can theoritically overclock an E6600 to 3.6Ghz on DDR800 at 1:1 without overclocking the RAM? (assuming it will overclock that far of course, we're talking theory here!)

cheers
ewart

[Apoptosis]

Ewart,

I'm not going to be able to get the benchmarking done tongiht and I'm going out of town tomorrow!

Not sure if your back yet; I've learnt some new info.. if my understanding is correct I do not even need to overclock the RAM in my planned scenario..


I saw something somewhere that implied the max CPU speed @ 1:1 is:

[DDR2 rate] / 2 * [CPU Multipler]

So DDR2-800 / 2: = 400
E6600 @ 2.4Ghz has a multiplier of 9.

So max speed without overclocking RAM is 9 * 400 = 3600mhz

perhaps someone knows if this is accurate? so in this case I can theoritically overclock an E6600 to 3.6Ghz on DDR800 at 1:1 without overclocking the RAM? (assuming it will overclock that far of course, we're talking theory here!)

cheers
ewart

How To Find Memory Clock Frequencies For AMD:

For example... Let's say we had an AMD Athlon64 FX-62 processor running at factory DDR2-800 speeds. To understand what is going on inside we can do simple math and see.

14 (CPU multiplier) x 200 MHz (motherboard clock speed) = 2800 MHz / 7 (memory divider) = 400 MHz (DDR2 frequency of 800MHz)



How To Find Memory Clock Frequencies For Intel:

For example... Let's say we had an Intel Core 2 Duo E6600 processor running at factory DDR2-800 speeds like you are wanting to buy. To understand what is going on inside we can do simple math and see.

9 (CPU multiplier) x 266 MHz (Front Side Bus Speed) = 2400 MHz
Take the 266MHz FSB and run a memory divider of 2:3 on it and you will get 399 MHz (DDR2 frequency of 800MHz).

On Intel you can run a 1:1 divider at 266MHz FSB and it will give you 533MHz memory or a 4:5 divider to get 667Mhz memory speeds. On intel it's all about the dividers uses and the FSB. if you overclock your system you will be increasing the FSB. Let's say you overclock to 325MHz FSB... Here are your memory choices (depends on board) at 325MHz FSB

1:1 - 650MHz
4:5 - 812MHz
2:3 - 975MHz

It really depends on your multi and nothing more!




The memory frequency is based off the front side bus on Intel processors.

[Ewart]

How To Find Memory Clock Frequencies For Intel:
For example... Let's say we had an Intel Core 2 Duo E6600 processor running at factory DDR2-800 speeds like you are wanting to buy. To understand what is going on inside we can do simple math and see.
9 (CPU multiplier) x 266 MHz (Front Side Bus Speed) = 2400 MHz
Take the 266MHz FSB and run a memory divider of 2:3 on it and you will get 399 MHz (DDR2 frequency of 800MHz).

Thanks; don't think I need to overclock the RAM then, so no need for any testing thanks. cheers

[injun]

Ewart,

I'm not going to be able to get the benchmarking done tongiht and I'm going out of town tomorrow!

Not sure if your back yet; I've learnt some new info.. if my understanding is correct I do not even need to overclock the RAM in my planned scenario..


I saw something somewhere that implied the max CPU speed @ 1:1 is:

[DDR2 rate] / 2 * [CPU Multipler]

So DDR2-800 / 2: = 400
E6600 @ 2.4Ghz has a multiplier of 9.

So max speed without overclocking RAM is 9 * 400 = 3600mhz

perhaps someone knows if this is accurate? so in this case I can theoritically overclock an E6600 to 3.6Ghz on DDR800 at 1:1 without overclocking the RAM? (assuming it will overclock that far of course, we're talking theory here!)

cheers
ewart

How To Find Memory Clock Frequencies For AMD:

For example... Let's say we had an AMD Athlon64 FX-62 processor running at factory DDR2-800 speeds. To understand what is going on inside we can do simple math and see.

14 (CPU multiplier) x 200 MHz (motherboard clock speed) = 2800 MHz / 7 (memory divider) = 400 MHz (DDR2 frequency of 800MHz)



How To Find Memory Clock Frequencies For Intel:

For example... Let's say we had an Intel Core 2 Duo E6600 processor running at factory DDR2-800 speeds like you are wanting to buy. To understand what is going on inside we can do simple math and see.

9 (CPU multiplier) x 266 MHz (Front Side Bus Speed) = 2400 MHz
Take the 266MHz FSB and run a memory divider of 2:3 on it and you will get 399 MHz (DDR2 frequency of 800MHz).

On Intel you can run a 1:1 divider at 266MHz FSB and it will give you 533MHz memory or a 4:5 divider to get 667Mhz memory speeds. On intel it's all about the dividers uses and the FSB. if you overclock your system you will be increasing the FSB. Let's say you overclock to 325MHz FSB... Here are your memory choices (depends on board) at 325MHz FSB

1:1 - 650MHz
4:5 - 812MHz
2:3 - 975MHz

It really depends on your multi and nothing more!




The memory frequency is based off the front side bus on Intel processors.

Hi all, (new here) and currently wanting to build an ASUS/Intel 975X X6800 PC and browsing to find all the latest performance part info for this set up. I would like to see about maximizing the X6800, but being early in it's release I see the Mobo (overclocking) support is limited at this time. So far for RAM, from what I've been reading for maximum results I should be between the hard to find "low latency" DDR2 Corsair 800MHz TWIN2X2048-6400C3 and/or perhaps the 1066MHz Twin2X2048-8500C5?

The 1066MHz 8500C5 technically isn't supported on the ASUS P5W DH Deluxe currently, however I have read that it can be used (although limited). Is it true for this particular ASUS Mobo that the memory bus can only work at 1066MHz frequency with the CPUs running at 266MHz FSB? Is this issue dependent at all on the CPU or any components capacity?

If I understand the above calculations for overclocking, RAM selection is very important in order to overclock well, correct? So theoretically with the Core 2 X6800 Extreme and 1066MHz of RAM a possible 1:1 yield is 5863MHz or approximately 5.73GHz CPU output? Is this correct?

I guess also to be successful the Mobo, Chip set and RAM must be able to adjust with the Core 2. Not sure how the CPU would hold up or what kind of heat control would be needed at 5+GHz?

Anyway besides all the overclocking possibilities on this new Intel CPU I think I would just be happy within the cool and stable 3 to 4GHz. So what RAM would be best for both everyday use and/or possibly maximum overclocking potential?

Thanks for all the insight so far.

[Ewart]

ah, now for the blind to lead the blind!

here is an example using the default X6800 multipler of 11 at default
speed, and also at and overclock of the fsb to 325mhz at both 1:1 and 4:5 and 2:3

11 x 266(fsb) = 2.926Ghz, default speed, ram is 533mhz at 1:1
11 x 325(fsb) = 3.575Ghz, overclocked, ram is 650mhz at 1:1
11 x 325(fsb) = 3.575Ghz, overclocked, ram is 812mhz at 4:5
11 x 325(fsb) = 3.575Ghz, overclocked, ram is 975mhz at 2:3

ok, here's a more extreme overclock
11 x 350(fsb) = 3.850Ghz, overclocked, ram is 700mhz at 1:1
11 x 400(fsb) = 4.400Ghz, overclocked, ram is 800mhz at 1:1

you won't get to 4.4ghz let alone 5ghz IMHO unless you have a lucky break or liquid cooling or both.

if you've got excess money to burn then (a) give me some! and b) go ahead and get expensive ram, but personally it seems like a lot extra for marginal change in performance. If your more financially stretched put the money where you'll get the best return, hard drive, video card etc..
eg, I could buy C3 ram for $1000 now, a $250 raptor offers better return overall.

part of my thinking is if I did invest mega $$$ I only retain the 'peak' performance for a few months until a new processor device comes out.. eg: whoever paid $1000 for a FX62 recently got the best perfomance for sure. but now of course I can come along and get better performance for $300.

hope that helps, good luck with your overclocking!

cheers
ewart

[injun]

ah, now for the blind to lead the blind!

here is an example using the default X6800 multipler of 11 at default
speed, and also at and overclock of the fsb to 325mhz at both 1:1 and 4:5 and 2:3

11 x 266(fsb) = 2.926Ghz, default speed, ram is 533mhz at 1:1
11 x 325(fsb) = 3.575Ghz, overclocked, ram is 650mhz at 1:1
11 x 325(fsb) = 3.575Ghz, overclocked, ram is 812mhz at 4:5
11 x 325(fsb) = 3.575Ghz, overclocked, ram is 975mhz at 2:3

ok, here's a more extreme overclock
11 x 350(fsb) = 3.850Ghz, overclocked, ram is 700mhz at 1:1
11 x 400(fsb) = 4.400Ghz, overclocked, ram is 800mhz at 1:1

you won't get to 4.4ghz let alone 5ghz IMHO unless you have a lucky break or liquid cooling or both.

if you've got excess money to burn then (a) give me some! and b) go ahead and get expensive ram, but personally it seems like a lot extra for marginal change in performance. If your more financially stretched put the money where you'll get the best return, hard drive, video card etc..
eg, I could buy C3 ram for $1000 now, a $250 raptor offers better return overall.

part of my thinking is if I did invest mega $$$ I only retain the 'peak' performance for a few months until a new processor device comes out.. eg: whoever paid $1000 for a FX62 recently got the best perfomance for sure. but now of course I can come along and get better performance for $300.

hope that helps, good luck with your overclocking!

cheers
ewart

Thanks for the insight, I am learning as I go.

No I don't have money to burn, but I am willing to spend a little extra to get the best just so I can appreciate it's performance. It's time for me to upgrade from my humble 6 year old 800MHz Pentium III and I thought I might as well go for broke with all this talk about the new Core 2. That also included the 10K Raptor drive among other things.

As you and others have pointed out during my search that an efficient budget might be the better way to go and still get a really fast system. I was looking into the RAM portion of the build and was obviously drawn too low latency with large bandwidth to really send it through the roof. Small things at the RAM level probably would be hard pressed to even notice from what I understand.

I am considering the E6700 as well. I've also seen some of the early overclock numbers on the entry level E6300 that impressed me but I think the 4Mb L2 would be a considerable improvement. I'm also aware of the up and coming Quad 4 technology but have read also of the CPU race getting way ahead of the actual needs. If I waited for every new advance I would never enjoy the benefits of today's technology. I am still using pre-2000 equipment and the Extreme X6800 looked like a lot of fun. I am probably going to wait for the support and all the backordered stock to catch up, maybe by then I will have a better idea of what I want versus what I really need.

Cheers

[Apoptosis]

If you are on a pre-2000 system moving to a conroe would be a huge leap in performance... It's really an amazing processor.

[Ewart]

I'm also aware of the up and coming Quad 4 technology but have read also of the CPU race getting way ahead of the actual needs.
Cheers

Sounds cool eh. I must own one! For me I'm thinking E6600 now clocked to run the same speed (or faster!) than the X6800, then in 6-8 months hopefully I will still have enough money left to grab a medium range Quad processor and drop it in the slot if it's compadible.

cheers
ewart

[injun]

If you are on a pre-2000 system moving to a conroe would be a huge leap in performance... It's really an amazing processor.

That was my thought too. I could go with any of the other cpu's from the last 5 years and still appreciate the differences for sure but today's Core 2 is just too good to pass up.

[atlr]

Question: What was the divider and/or memory frequency when the DDR2-666 modules were used with the AM2 4800+?

Do I understand the article correctly that the memory dividers are whole numbers?

The DDR2-800 operated with a memory divider of 6.
2400/6=400

Was the DDR2-666 underclocked with a divider of 8?
2400/8=300

[Apoptosis]

No clue man... I wrote that over 8 months ago and the test notes are long gone. It looks like I did that review on C2D anyway.