PC8500 1066 DDR2 vs. PC6400 800 DDR2

[lamere]

i'm thinking of going from corsair ddr2 800mhz to (insert name brand here) 1066mhz...

is it that much of a difference? i heard that for my CPU (Q9450 and rest in sig) that the 1066 is the way to go, and if it is, whats the best brand.....i was looking at corsair dominator high performance rm but am getting turned off by all the DOA sticks ppl are getting in the reviews......

thanks

 

[DSF]

If you're not overclocking then don't worry about it. The performance difference, if any, will be minimal.

 

[z1ggy]

Agreed. I am in love with my G.skill DDR2 800 2gb's and they OC too.

 

[supremelaw]

Some Corsair DDR2-1066 is just overclocked DDR2-800.

A lot depends on whether you want to overclock, or not.

The Q9450 has a stock FSB of 1333 MHz:

http://www.newegg.com/Product/...x?Item=N82E16819115042


To achieve a target FSBRAM ratio of 1:1, then:

1333 / 4 = 333 MHz raw CPU Bus Speed (using CPU-z nomenclature)

333 raw DRAM Bus Speed x 2 = 666 MHz rated DRAM speed ~= DDR2-675

Thus, at 1:1 you really only need DDR2-675, so DDR2-800 is quite adequate.
This is the prior "sweet spot".


The next step up at 1:1 would be an FSB of 1600 MHz:

1600 / 4 = 400 MHz raw CPU Bus Speed

400 x 2 = DDR2-800 / PC2-6400

This is the latest "sweet spot" at 1:1 FSBRAM ratio.


Thus, DDR2-1066 is not necessary for 1:1 ratios at stock settings,
given the latest FSB speed of 1600 MHz.


p.s. We just upgraded our D 945 workstation from 2GB of DDR2-800 Dominator
to 4GB of DDR2-1066 Dominator: we couldn't set the memory timings any
higher than DDR2-800, because the BIOS requires an FSB Bus Speed of 200 MHz.
Later, after we upgrade to a Q6600, we can increase the Bus Speed to 266 MHz,
and at that setting the BIOS in our P5W64 WS Professional shows DDR2-1066
as a new option that not shown when the Bus Speed is only 200 MHz.


Sincerely yours,
/s/ Paul Andrew Mitchell, Inventor and
Webmaster, Supreme Law Library

All Rights Reserved without Prejudice



Link removed, check your PM box.
-Schadenfroh (AT Mod)

 

[supremelaw]

Another incremental factor when comparing those 2 DRAM types
is that SPD for larger density DIMMs generally specifies looser timings.

Thus, our 2 x 1GB DDR2-800 Corsair Dominators have an SPD of 4-4-4-12-22-2t .

By comparison, our 2 x 2GB DDR2-1066 Corsair Dominators have an SPD of 5-5-5-15-22-2t .


Corsair's website has excellent reports of stock and overclocked settings for numerous memory/motherboard combos.


Sincerely yours,
/s/ Paul Andrew Mitchell, Inventor and
Webmaster, Supreme Law Library

All Rights Reserved without Prejudice



Link removed, check your PM box.
-Schadenfroh (AT Mod)

 

[n7]

The majority of "DOA" DDR2-1000+ kits aren't so much DOA as they are being installed & used by n00bs who don't understand they are buying RAM for overclocking, not n00bie-friendly stuff you can just pop in & magically expect wonderful results.

I assume you are going to overclock that Q9450, let's say to around 8x450 (3.6 GHz) levels.

That means 450 MHz FSB, so you need something capable of DDR2-900 minimum.
Most good DDR2-800 kits will overclock to that speed, but getting something DDR2-1000+ won't hurt to be safe either.

1:1 isn't a sweet spot; it's the minimum spot.
Higher ratios like 5:6, 4:5, 3:4, will offer better performance, albeit by a small amount.

If you go with DDR2-1066, & you were running 8x450, you could likely do 5:6 (DDR2-1080).

If you're new to OCing RAM or don't have the patience to spend some time in the bios, then running 1:1 is easier.

 

[MageOfGeno]

Which would be better though OCing 4 GIG of DDR-800 RAM to 900 or useing just 2 GIG of DDR2-1066 RAM? im assuming it would be useing the 4 GIG of 800 but there could be some factors im un aware of.

 

[supremelaw]

I'm not an expert on this subject, so please correct me promptly
if I make any errors here.

I never will be an expert, either, because I'm a fanatic about stability
at stock settings: if I need more performance, I look into buying
components that have higher performance at stock settings.

From my daily reading on the Internet, I see knowledgeable reviewers
agreeing that higher density modules come with more relaxed SPD timings;
and, 4 DIMMs will put more stress on the Northbridge than 2 DIMMs.

I've confirmed both observations, from my own experience.

I guess it boils down to what you mean by "better"?

"Better" to me means the highest feasible performance
given absolute rock-solid stability.

After 38 YEARS in IT, I can't honestly convey how nice it
really is that my production workstation does NOT halt
even once during a normal work day: by comparison,
in 1980 our super minicomputer would crash at least
twice every day, requiring a laborious re-start --
from the operator console.

If some setting introduces ANY instability in our workstations,
then that's "WORSE"! That's my bias here, OK?

Thus, OCing 2 DIMMs should be easier than OCing 4 DIMMs, and
OCing 2 x 1GB DIMMs should be easier than OCing 2 x 2GB DIMMs.

And, that generality very probably varies significantly from one
RAM manufacturer to the next.

Bear in mind that some DDR2-1066 is really just overclocked DDR2-800 anyway.

So, if you intend from the start to OC DDR2-800, then make the jump to DDR2-1066
because the latter will probably give you more headroom -- particularly if it is
NOT just overclocked DDR2-800.

DDR3 is an unknown quantity to me, for the most part, because I have no
direct experience with it (yet). From the technical specifications I am reading,
however, it appears to have a much higher OC headroom (MAX Headroom, maybe?):
the highest bandwidths are happening now with DDR3.

Hopefully, it will plunge in price as did DDR2-800 4-4-4-12 (which is still a very
good choice for stability fanatics like me).


Sincerely yours,
/s/ Paul Andrew Mitchell, Inventor and
Webmaster, Supreme Law Library

All Rights Reserved without Prejudice



Link removed, check your PM box.
-Schadenfroh (AT Mod)

 

[DSF]

If you need more headroom than DDR2-800 I would go with DDR2-1000. It offers performance very close to 1066 with a price very close to 800.

 

[OCChronic]

Originally posted by: n7
The majority of "DOA" DDR2-1000+ kits aren't so much DOA as they are being installed & used by n00bs who don't understand they are buying RAM for overclocking, not n00bie-friendly stuff you can just pop in & magically expect wonderful results.

I assume you are going to overclock that Q9450, let's say to around 8x450 (3.6 GHz) levels.

That means 450 MHz FSB, so you need something capable of DDR2-900 minimum.
Most good DDR2-800 kits will overclock to that speed, but getting something DDR2-1000+ won't hurt to be safe either.

1:1 isn't a sweet spot; it's the minimum spot.
Higher ratios like 5:6, 4:5, 3:4, will offer better performance, albeit by a small amount.

If you go with DDR2-1066, & you were running 8x450, you could likely do 5:6 (DDR2-1080).

If you're new to OCing RAM or don't have the patience to spend some time in the bios, then running 1:1 is easier.

Heyya, n7 =)

I agree with you that more ratios than 1:1 can give exceptional performance. I'm running an X38-DQ6, Corsair Dominator DDR2 1066-CL5, 5,5,15 2GB kit & an E8400 @ 475 x 8 with a 5:6 divider(DDR2 1140-CL5,5,5,18,2T), 400 FSB strap & Performance level(Trd) @ 7. It's rock solid 24/7 stable & my Everest memory scores are around 10,000 MB/s for all 3 tests. Memory latency is around 52ns. :thumbsup:

 

[supremelaw]

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Thanks, all!


Sincerely yours,
/s/ Paul Andrew Mitchell, Inventor and
Webmaster, Supreme Law Library

All Rights Reserved without Prejudice