PC2-4200,5300,6400: Whats the difference? Same in price

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oscaryu1

VIP Member
Same price?! Go for the highest your motherboard can support!

Dumbed down, the higher the number, the faster the RAM.
 
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PC eye

banned
That model supports DDR2 800 PC2-6400 memory as the fastest speed. The thing to look at before ordering is what memory you already have installed as far as speed and type.

You don't want to mix performance memory if you are running standard or value ram presently. If you have 2gb of DDR2 533 another 2gb of DDR2 800 would see the faster 800 slowed to 533mhz. When going to replace the 3rd 1gb dimm you want to match as closely as possible or replace the first 2gb in preference of seeing a faster memory.
 
TechShark

TechShark

Member
So i checked what i have its, 2x1gb Corsair Twinx (XMS) Heat Shield DDR2 PC2-6400 800mhz, So i should get another pair of the 6400?
 
P

PC eye

banned
That's the DDR2 800 performance memory by Corsair there. Corsair is a good brand to start off with plus you wouldn't want to mix another brand's pair and see a difference in timings.

When going to order one thing to note is that are different 2gb kits of the xms series memory to choose from. Those will also see differences in timings and voltages plus there's a Dominator version. http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2000170147%2050001666%201052108080%201052416064%201052308477&name=2GB%20%282%20x%201GB%29

You'll want to match what you have now with the correct pair chosen from the several kits at the link there.
 
P

PC eye

banned
That was partly my fault there having forgotten to mention a freeware called CPU-Z that will show the timings as well as the frequency the memory is operating at. http://www.cpuid.com/pcwizard.php

Now don't get alarmed when seeing something like what is in the image here as far as the frequency is concerned. While listed as 800 you have to add the multiplication factor of "2" when looking at that with what CPU-Z shows. That how DDR, DDR2, DDR3 memory works.



Think of a single lane road being widened for a second lane to understand doubling the bandwidth.
 
T

TrainTrackHack

VIP Member
Think of a single lane road being widened for a second lane to understand doubling the bandwidth.
Click to expand...
That is called dual-channeling. DDR memory doesn't double the actual bandwidth; the bandwidth remains 64-bit (or 128-bit for dual-channel). DDR simply doubles the number of transfers per clock from 1 to 2, hence the name Double (or Dual) Data Rate.

you have to add the multiplication factor of "2"
Click to expand...
There's no such thing as a "multiplication factor" as far as mathematics are concerned.
 
StrangleHold

StrangleHold

Moderator
Staff member
PC eye said:
Now don't get alarmed when seeing something like what is in the image here as far as the frequency is concerned. While listed as 800 you have to add the multiplication factor of "2" when looking at that with what CPU-Z shows. That how DDR, DDR2, DDR3 memory works.



Think of a single lane road being widened for a second lane to understand doubling the bandwidth.
Click to expand...

DDR
PC eye you have been told this hunderds of times. DDR is not like a 2 lane road. DDR2 800 runs at 400mhz period. Unlike plain SDRAM, DDR can transfer data on the rising and falling of a single clock cycle. There is no second lane. It just has the capability of transfering twice the amount of data then plain SDRAM. The only reason its referred to as 800 is it would take a plain SDRAM stick of memory running at 800mhz to tranfer the same amount of data.
 
StrangleHold

StrangleHold

Moderator
Staff member
tyttebøvs said:
Not if you overclock it :p
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Yea a few weeks ago, cant remember exactly how it went, (pretty close). DDR2 800 was two sticks running at 400 + dual channel, so two channels at 400mhz = 800mhz. I was in amazement, laughed so hard my right eye went bloodshot.
 
gamerman4

gamerman4

Active Member
tyttebøvs said:
Not if you overclock it :p
Click to expand...

if you overclock it then it will no longer be DDR2-800 then would it?
it would be DDR2-[insert new overclocked speed]

You obviously misinterpretted what PC meant, like all of us do all the time someone proves him wrong
Click to expand...

I second that, he has decent information but he loves using the verb "see" in almost every sentence which is epic fail when you are trying to actually understand him.
 
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gamerman4

gamerman4

Active Member
Now my right eye just went bloodshot...
Click to expand...

Might want to get that checked out... :p

imsati said:
I'm not sure ya fully understood the hidden sarcasm in my last Post.
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i know what you meant but I don't believe his information sucks all the time, just most of the time so "decent" is a crappy enough word to fit without actually claiming his info completely sucks all of the time.
 
gamerman4

gamerman4

Active Member
tyttebøvs said:
Should that be multiplied by two, or ...?
Click to expand...

DDR2-800 has a memory clock speed of 200mhz and an I/O bus clock speed of 400mhz (what Stranglehold mentioned)

Overclocking a CPU FSB also overclocks the internal RAM clock speed.

CPU: (ill use mine as an example) Q6600
advertised FSB = 1066mhz
base FSB = 266mhz
multiplier = 9
clock speed= 2400mhz

this translates into RAM as
base FSB of CPU = memory clock speed of RAM (when using a 1:1 divider)
so
266mhz FSB = 266mhz memory clock
266FSB translates into 1066mhz FSB so you would need DDR-1066
a 200mhz FSB would need DDR2-800

so to answer your question when you see DDR2-800 you divide the "800" by 4 to get the base clock speed. This helps when overclocking because it is best to run your RAM at the same base clock as your CPU FSB.

Once you overclock it is no longer DDR2-800 but rather a higher speed.
 
TechShark

TechShark

Member
Jeez, I know a fair amount of information above the average computer user but you guys a running circles around me haha. I checked my timing with the cpu-z. it is the 5-5-5-18.
I currently have a total of 4 slots, 1 is open. 2 have the corsair memory mentioned earlier. and one slot has some different brand of 1g memory. I'm going to remove the 1g and replace it with 2 of the same corsair memory of 5-5-5-18 timing. Will this be a good decision for optimum performance?
 
gamerman4

gamerman4

Active Member
TechShark said:
Jeez, I know a fair amount of information above the average computer user but you guys a running circles around me haha. I checked my timing with the cpu-z. it is the 5-5-5-18.
I currently have a total of 4 slots, 1 is open. 2 have the corsair memory mentioned earlier. and one slot has some different brand of 1g memory. I'm going to remove the 1g and replace it with 2 of the same corsair memory of 5-5-5-18 timing. Will this be a good decision for optimum performance?
Click to expand...

The timing doesn't make a huge difference but having two sticks of RAM will give you the benefit of running dual channel which will increase your performance beyond what the timings are but you will have less RAM so you are going to have to ask yourself if you need more RAM or more memory bandwidth, I would just go with keeping the 3 sticks, dual channel doesn't make a huge difference either. I have 2 sticks and tried them in single and dual channel with only a difference between 5.0 and 5.3 on the Vista Exp. Index. Of course, you could always just try it yourself and take one stick out, and run some benchmarks. You might benefit from the extra bandwidth in dual channel if you play games that don't need past 2GB of RAM but if you do things like video editing then more RAM will be better than higher bandwidth.
 
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