PC2-4200,5300,6400: Whats the difference? Same in price
- Thread starter TechShark
- Start date
Timing will effect the amount of data the CPU receives in a certain time regardless of the mhz. its running at.
I,m going to go stupid noob and use cars. Cars on two different roads. All going 30mph. If the red lights last a fraction of a second longer on the first road, then there will be more cars get to the other end on the second road faster. Doesnt matter if all cars were traveling at 30mph.
I,m going to go stupid noob and use cars. Cars on two different roads. All going 30mph. If the red lights last a fraction of a second longer on the first road, then there will be more cars get to the other end on the second road faster. Doesnt matter if all cars were traveling at 30mph.
scooter
banned
What type of cars are on the road...
some accelerate faster....say there was like 15 yugos and 1 lamborghini...
gamerman4
Active Member
Like tyttebovs said, the internal clockspeed doesn't matter (since it's half of the external speed and that can't be changed). The memory bus clockspeed is still the same as FSB clockspeed when the divider is set to 1:1. DDRn RAM is rated at double the external clockspeed, or the bus speed; hence, the rating of Dual Data Rate RAM should be half of the rating of the Quad Data rate FSB. Since I'm a nice boyP), I bolded the incorrect part for you; as I said, the external memory clock is the one that runs in sync with the FSB when the divider is set to 1:1. The internal clock speed, in your example, would be the half of the external clock, or 133MHz, whereas you seem to think that when the divider is 1:1 the FSB the internal clockspeed of the RAM will be synced with the FSB - this is incorect.
From wikipedia: http://en.wikipedia.org/wiki/Pumping_(computer_systems)
Alright that's fine, your argument is agreeable, I must have just misunderstood the wiki article at first. Thanks for clearing that up. I learned about overclocking when I had an AMD CPU and the old Athlon 64s were also double-pumped.
Here is how I got confused:
My motherboard uses the internal clock as designated by the SPD of the RAM in order to do it's calculations.
The minimum RAM multiplier is 2.66 which is actually a .66 divider with the inevitable double-pumping added in there to simplify things.
The 1:1 ratio is actually a 2:1 RAM:CPU ratio since DDR2 has to run at twice the clock speed of DDR to make up for the increased latency.
My motherboard shows the maximum multiplier at 4x which is the 2:1 ratio (2 for double-pumping and 2 for double the rate)
My confusion was in that my motherboard actually uses the 200mhz internal clock of DDR2-800 (266 internal for 1066) and just combines both the double-pumping (which cannot be changed) and the data rate (which can be changed)
here is how I assume my motherboard calculates the clocks for memory:
(CPU FSB) x (2 + [data rate multiplier])
the 2 is constant because you cannot change the fact that it is double-pumped and the data rate multiplier is like a RAM divider.
So I was confusing a 1:1 ratio with what was actually a 2:1 ratio
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The SPD doesn't list the internal/chip speed. It lists the speed in which the ram module talks to the outside world.
The internal speed is only relevant, if you look at how the module is constructed. What is relevant is how the bus between the module and memory controller works. And this bus is double pumped.
Also remember that the latency numbers are relative to how fast the bus is running. A "5" takes longer at 200Mhz than it does at 400Mhz
The internal speed is only relevant, if you look at how the module is constructed. What is relevant is how the bus between the module and memory controller works. And this bus is double pumped.
Also remember that the latency numbers are relative to how fast the bus is running. A "5" takes longer at 200Mhz than it does at 400Mhz
gamerman4
Active Member
ok then could you explain why the motherboard multiplies by 4 to get 800mhz for my RAM from an FSB set to 200mhz?
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Its not, its multiplied by 2. The memory is running at 400mhz. You can say 800mhz because of the memory being DDR itself but theoredically its running at 400mhz.
gamerman4
Active Member
But why would the BIOS say memory multiplier: 4
I was looking around the subject and here is what THG states
"A 3.73 GHz Pentium 4 Extreme Edition processor was our chosen chip, because it works with the system clock set to 266 MHz to produce FSB1066; with a 1:1 FSB/memory ratio, that also means the memory runs at DDR2-1066."
This would mean my statement was true and that in a 1:1 ratio a 266 chip is not DDR2-533 (which when divided by 2 would equal 266) but rather DDR2-1066."
The P4EEs are also quad-pumped so they are no different than a Core2 in the situation.
CPU-Z of DDR2-1066
it shows that the frequency is roughly 1066/4
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tlarkin
VIP Member
Yup it is just more bandwidth (more data throughput) really. The throughput you can put on your RAM means the faster instruction sets can be placed and paged from RAM.
Does it make a difference?
yes if you push your machine to use more bandwidth. It can also create a bottle neck if it is moving too fast for the rest of your system. You are only as fast as your slowest component, which is almost always the hard drive.
But why would the BIOS say memory multiplier: 4
I was looking around the subject and here is what THG states
"A 3.73 GHz Pentium 4 Extreme Edition processor was our chosen chip, because it works with the system clock set to 266 MHz to produce FSB1066; with a 1:1 FSB/memory ratio, that also means the memory runs at DDR2-1066."
This would mean my statement was true and that in a 1:1 ratio a 266 chip is not DDR2-533 (which when divided by 2 would equal 266) but rather DDR2-1066."
The P4EEs are also quad-pumped so they are no different than a Core2 in the situation.
CPU-Z of DDR2-1066
it shows that the frequency is roughly 1066/4
I dont know any other way to explain it to you. The Screenshot looks like a stick of 512mb. DDR2 533 overclocked a couple of mhz. Memory is not Quad pumped.
gamerman4
Active Member
Having never said that DDR is quad-pumped, here is my explanation.
I'm going to go back in time for a sec to DDR...
DDR RAM:
-your FSB dictated exactly your memory clock speed (AFAIK the memory, not the bus)
-so a 200mhz FSB would mean 200mhz memory clock
- DDR is double pumped so that 200mhz mem clock means 400mhz at the bus
-this equated to DDR-400
DDR2 RAM:
-your FSB still dictates your mem clock
-200mhz FSB means 200mhz mem clock
-DDR is double pumped so it is a base of 400mhz at the bus
-the DDR2 bus operates twice as fast as a DDR bus so that 400mhz operates at 800mhz, giving DDR2-800
Based on all the evidence I have found, I am convinced that the memory clock, not the bus clock, is what changes with your clock speed.
Now if you could find somewhere that states that it is the bus and not the memory clock that gets modified by your CPUs FSB then I will try to recreate my hypothesis in favor of the new data. So far I stand by my original statement.
No, just because something it double or quad pumped does not mean that the bus runs at that mhz. If we are talking about a (1:1). If you have a 266 FSB quad pumped/1066 the bus is still running at 266. So a 1:1 with memory would be running DDR2 533 because both base clocks are running at 266.
gamerman4
Active Member
that would apply to DDR RAM, DDR2 has a bus that runs twice as fast as a DDR bus, therefore it further doubles the double-pumped rate.
I think your getting mixed up between the External clock speed and the Data bus speed, DDR2 533 has a External clock speed of 266mhz but has a Data bus speed of 533 Mbps. DDR2 has 4 bit prefetch where DDR has 2 bit.
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gamerman4
Active Member
DDR2-533 may have an external bus clock of 266 but it has an internal memory clock of 133.
I am pretty sure overclocking relies on the internal memory clock as its base.
Also that CPU-Z pic was of DDR-1066, not 533, regardless of being dual or quad pumped, it runs 4 times as fast as its base speed because of 2 different factors, the bus speed and the double data rate.
I am pretty sure overclocking relies on the internal memory clock as its base.
Also that CPU-Z pic was of DDR-1066, not 533, regardless of being dual or quad pumped, it runs 4 times as fast as its base speed because of 2 different factors, the bus speed and the double data rate.
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Part of what you said it true. But think about the double your talking about with DDR2. Internal clock speed of 133/external of 266. There is your double. You dont double it from the 266 of the external. DDR only means you get two data transfers on each clock cycle, it does not increase the bus speed. So 1:1 with a quad pumped FSB 266/1066 is DDR2 533. We are talking about bus speed not transfer rates.Look at it this way: if the (double pumped) bus between the memory controller and ram is running at 266 (533) Mhz, how in earth will you transfer data from a ram module running at 533 (1024) Mhz?
Answer: You can't.
All the DDRx modules differ internally, but their connection to the outside world (the double pumped bus) is the same, and so is the calculations.
If you connect a raid controller to your computer, and build an advanced setup, will the OS address this any different than it does a normal drive? No.
If you connect a keyboard to a computer across the world, through an ip-based kvm switch, will the computer care? No.
Will your graphics care what type of display device you connect to its vga port? No.
The internals doesn't matter.
Answer: You can't.
All the DDRx modules differ internally, but their connection to the outside world (the double pumped bus) is the same, and so is the calculations.
If you connect a raid controller to your computer, and build an advanced setup, will the OS address this any different than it does a normal drive? No.
If you connect a keyboard to a computer across the world, through an ip-based kvm switch, will the computer care? No.
Will your graphics care what type of display device you connect to its vga port? No.
The internals doesn't matter.
gamerman4
Active Member
because the 533mhz bus is transferring data twice as fast as it was in the original DDR spec.
The base internal clocks have not changed between DDR and DDR2 (except with the addition of a higher 266mhz clock) the only difference is that the bus is transferring twice as fast as before. DDR2-800 and DDR-400 have the same internal clock and when Intel used DDR, the cpus were still quad pumped and the ram was still double pumped and you still needed DDR-400 for optimal performance even though the FSB and bus (in DDR the bus and internal clock are the same) were both running at 200mhz.
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