PC2100, PC2700 etc. meaning 1

[fenix]

PC1600 200mhz (DDR200)
PC2100 266mhz (DDR266)
PC2700 333mhz (DDR333)
PC3200 400mhz (DDR400)
PC3500 433mhz (DDR433)
PC3700 466mhz (DDR466)
PC4000 500mhz (DDR500)
PC4300 533mhz (DDR533)


Can someone please verify that these ratings are for
the memory bus speed.

If so, is there a way to determine what the front side bus speed is by the PCxxxx name ?

Or does it vary by chipset ?




thx much

 

[SYAR2003]

E.g PC3200 means memory bandwith upto 3,2Ghz .
And DDR400 means that it's DDR speed is 400mhz
thats double of the fsb clock speed given to the memory module . DDR = Double Data Rate .

With DDR, under optimal conditions twice as much data can be obtained from the
memory subsystem during the same amount of time.

With standard SDRAM, data is transferred from the memory
to the processor when the clock signal goes from LOW to HIGH.
With DDR, data is transferred not only when the clock signal goes from LOW to HIGH, but also when the clock signal goes from HIGH to LOW.
Thats why it's called DDR ,twice as much data on each clock syclus as with standard SDRAM.

 

[SYAR2003]

PC1600 200mhz (DDR200) max memory fsb=100mhz
PC2100 266mhz (DDR266) max memory fsb=133mhz
PC2700 333mhz (DDR333) max memory fsb=166mhz
PC3200 400mhz (DDR400) max memory fsb=200mhz
PC3500 433mhz (DDR433) max memory fsb=216mhz
PC3700 466mhz (DDR466) max memory fsb=233mhz
PC4000 500mhz (DDR500) max memory fsb=2500mhz
PC4300 533mhz (DDR533) max memory fsb=266mhz

If you can run the memory fsb in sync with cpu fsb
depends on witch of theese modules . And type of cpu , and
the motherboard and it's chipset . And last power(PSU).

E.g Atlon xp2500 Barton is a 166mhz cpu (actually 166*2~333mhz).
But in most cases it performs well upto 200mhz or even as high as 250mhz cpu fsb ,this if it's not getting to hot and the total clock frequenzy is not to high .

 

[SYAR2003]

Sorry a little type error here:
PC4000 500mhz (DDR500) max memory fsb=2500mhz

PC4000 500mhz (DDR500) max memory fsb=250mhz

 

[jsauce]

PC1600 DDR xxx = (100 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 1600 MB/s available bandwidth.

PC2100 DDR xxx = (133 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 2128 MB/s available bandwidth.

PC2400 DDR xxx = (150 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 2400 MB/s available bandwidth.

PC2700 DDR 333 = (166 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 2656 MB/s available bandwidth.

PC3000 DDR xxx = (183 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 2928 MB/s available bandwidth.

PC3200 DDR 400 = (200 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 3200 MB/s available bandwidth.

PC3500 DDR 433 = (215 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 3440 MB/s available bandwidth.

PC3700 DDR 466 =(233 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 3728 MB/s available bandwidth.

PC4000 DDR 500 = (250 MHz Operating Speed) x (2x Rising & Falling) x (64-bit Bus) / (8 bits per byte) = 4000 MB/s available bandwidth


John D. Saucier
jsauce@magicguild.com
Certified Technician
Network Administrator

 

[SYAR2003]

jsauce ! i thought i said excactly that in the previous post .
(Except the formula)
Nice summary .

syar

 

[SkipCox]

If you didn't, I need to stop playing with computers.

Skip

http://home.comcast.net/~skip9/index.html

http://scc.i8.com

 

[kiddpete]

OK, I see part of what you guys are saying. I have a 2.66Ghz P4, and the fsb is 533Mhz. Does that mean it's too fast for any of the types listed? What memory would I use with it? Right now it has RDRAM PC1066, and I've wondered if that was the best choice.

 

[cdogg]

kiddpete,
Actually, it's a bit different when you're going from an AMD to Intel chipset. Most newer Athlons, for instance, use a 200Mhz FSB. DDR400 is the perfect match since it runs "double the speed" at 400MHz (DDR - Double Data Rate).

Going to Intel, the numbers game can get messy. For example, the P4 chipsets all use a multiplier of 4 on the FSB. So, a 533MHz FSB (the Northwood P4) is really just a 133MHz x 4. Therefore, regular DDR would fall behind because it would only be doubling the 133MHz to 266MHz. RAM at 266MHz is way behind the CPU FSB running at 533MHz.

Still with me? Hang in there! RDRAM overtook DDR briefly because of the higher clock speeds. PC1066, for example, runs at 1066MHz internally and has a memory bus speed of 533MHz to match the CPU's FSB. This was considered top-of-the-line until Intel shifted sides and started backing DDR. The next chipsets released supported an 800MHz FSB and Dual-DDR, which doubles the bandwidth of regular DDR. Therefore a DDR400 can now operate on an 800MHz memory bus to match the 800MHz FSB of the newer P4's.

If you're not in to fuzzy math, I don't blame you. However, the manufacturer SiS is about to release some newer motherboards that support PC1200 and PC1600 Dual-channel RDRAM. They should be able to bring some competition to the table for Dual-DDR for some time until DDR-II technology comes out. It may be the last breath for RDRAM.


~cdogg
[tab]"All paid jobs absorb and degrade the mind"
[tab][tab]- Aristotle
[navy]For general rules and guidelines to get better answers, click here:[/navy] faq219-2884

 

[fenix]

thanks cdogg! 'you da man'.....that's exactly the info I was looking for that I couldn't quite put together by researching.

5 star explantion...a keeper for future reference !

 

[fenix]

PS......to cdogg's explanation.

Can you briefly explain what dual channel DDR Ram is ?
and a and how it changes the speeds ?
(....I assume that it's double the normal DDR. )

I'm getting a Dell 8300 P4 3.0 800 fsb, with 400mhz dual channel DDR, so this has an underlying 200 mhz fsb (X 4) and the DDR doubles the 200mhz underlying fsb speed. YES ?

The only thing that I don't like about the whole package is that it only has a 250 watt p/s. But I don't do any gaming or graphics editing, (just real time advanced stock trading software), so do you think 250w is sufficient ? I've always heard that P4's suck up the power and getting a p/s over 300 is always better, but I guess they wouldn't put in a 250 if they were going to have problems with it. ?

thx again for any help on this

 

[fenix]

omitted: 875P chipset

 

[jurgen36]

Do not necessarely believe what the manufacturers do, it aint neccessarely ok. I would say that a 250 watt supply for a P4 3.0 is completely and utterly insufficient and it must be a joke. I use the P4 HT EE 3.2 processor and had to upgrade my supply from 400 watts to a 550 watt unit. It would otherwise not start up. So I suppose it must be a missprint. Better check up on it or buy another system. Good luck

Jurgen

 

[fenix]

would not start up ????

are you serious ?? your computer wouldn't boot up ???
-----------------------------------------------------

250 isn't a misprint and I was pretty amazed myself.

When I discovered that the 8300 xps version has a 460w I was pissed because they told me at order time there was no upgrade. Even though the XPS has a supposedly newly designed seperate compartment for shielding for the 460w, aren't all power supplies the same size ?

 

[cdogg]

fenix,
Intel still maintains that the minimum power supply rating needs to be 250W for the entire P4 line. See these links:

http://www.intel.com/support/platform/pentium4/cases.htm

http://www.intel.com/personal/resources/build/hardware.htm?iid=ipc+byoov_body_nextbyohw

However, the more devices you have in your system, the more wattage you need. I typically recommend 350W as the bare minimum for high-end P4's and video cards in one system. Anything at or above 400W should be plenty. In Jurgen's case, he could have either had a bad power supply or a generic one that had a high peak at 400W but a poor continuous rating. As long as you go with a name brand like Antec or Vantec, you should be fine.


As far as Dual-Channel DDR is concerned, theoretically you're right. Each DDR DIMM module is running at "double data rate" which means 200MHz x 2 = 400MHz. Then because their in Dual-Channel, the bus is 128 bits wide which effectively doubles the bandwidth again to the equivalent of 800MHz. Here's an illustration of the difference:

DDR400 (Single-Channel 64-bit): 8 bytes X 200MHz X 2 = 3.2 GB/s
DDR400 (Dual-Channel 128-bit): 16 bytes X 200MHz X 2 = 6.4 GB/s

More on this topic if you're interested:
thread602-752300


~cdogg
[tab]"All paid jobs absorb and degrade the mind"
[tab][tab]- Aristotle
[navy]For general rules and guidelines to get better answers, click here:[/navy] faq219-2884

 

[dakota81]

Yeah, the whole problem to me is the stupid "marketting" terms AMD & intel uses. Intel boards don't run at 800MHz, they run at 200MHz but have the bus widened to transfer up to 4 times as much data than the P3's could. So they decided to give us the "effective 800MHz" term because 800 > 200 and really, isn't that why most people buy newer computers?

AMD does the same thing, and they were first actually, but their data transfer between cpu & chipset is capped at half the potential of the P4's.

But on the other hand, all this "marketting" name-calling keeps those in the field ahead of those who aren't, so we can still charge people for building computers properly for them. =)

 

[garebo]

Getting back to the power supply thing, I have always believed that one should have at least 300 watts and 250 watts is better. However, Dell, HP, Gateway, and many or most name brand builders use these small 250 watt power supplies. I have even seen 185 watts and i think it was a P4 too!!
I would think that if a person added a super vid card, another burner, and another hard drive, he may run into trouble with the power supply.
But, i know a fella with a 200 watt power supply in a P4 1.7 and he added a second hard drive and a burner to the exising hard drive and cdrom, no trouble yet.
But hard drives dont use up a lot of watts!

 

[dakota81]

Commenting on the previous post on power supplies; harddrives & cd/dvd-roms really do not take up much power at all. A dvd-rom is higher at 20watts, but for a harddrive they take 15-20 to spin up, then a mere 7 or so watts to operate; most manufacturers post the information on their web sites.

And the one thing that you really have to question about PSU's is, how do they rate them? Is the specified wattage continuous or maximum power output, because that is a huge difference. A 250W continuous PSU is typically a 350W maximum PSU. On the other hand, a 250W maximum PSU is probably a 175W continuous PSU. Big difference if all they list is "250W". I'm just saying I really hate PSU labelling & wish they would supply both numbers on all PSU's.

 

[fenix]

OK thx all for the input. I understand now that dual channel is exactly what it says; 2 channels or 2 buses enabling twice the bandwidth to the MCH, and there needs to be at least one stick in each channel.
----------------------------------------------------------

cdogg, I read the tips and yes I could/should have done a search before posting.
----------------------------------------------------------

 

[garebo]

regarding the power supply issue, another thing.
The fans that get their power from the mobo apparently take up a lot of power, better to use the 12 volt molex supplied fans for the case, i believe, please correct me if i am wrong. Course the cpu fan is always connected at the mobo, i am talking about the case fan(s).