Difference between PC 130/133 Memory and DDR Memory

Can someone please tell me the difference between PC 130/133 memory and DDR memory? Also, if you can, tell me how I can know which motherboards will fit inside my HP Pavilion 6730 Desktop and how I know what CPU will fit as well. I am hoping to upgrade to 2.93 MHz CPU, 320 MB Hard drive, and a motherboard capable of handling this hardware and fitting into my computer casing. On advice from Minion I am updating, thanks Minion. I am looking to buy from TigerDirect if I am sure of what I am buying. Thank you.

 

u mean 320 gb instead of 320 mb hard drive, because with 320 mb u wouldnt be able to do much with anything with that

 

In addition to what ddp posted, SDRAM modules use only one side of the memory signal to the system to transfer data. DDR stands for Double Data Rate, meaning that type of memory is designed to use both sides of the signal for transfering data.

Think of SDRAM being a single lane road, and DDR being a two lane.

PC133 is the same as DDR266 (PC2100) in the respects that both run at 133mhz. However, the DDR using both sides of the signal means 133x2 or 266! If you wish to know the math on determining mhz from memory PC ratings, simply divide the number after PC by 8. (PC3200 = 400mhz)

Hope that helps!

 

So, since my computer takes the 'two notch' sdram pc130/133 stick it will not take the 'one notch' ddr stick. But new computers use ddr. Do I have that right? Thanks all.

 

Another question for Morph416: You said If I want to know the math in determining mHz from PC ratings I divide the number by 8. Where does that PC rating come from, what is it part of, is it the motherboard? Does this mean a memory PC rating of PC3200 mean the motherboard will support a maximum cpu speed of 400mHz? Thanks again.

 

@putray

Sorry for the confusion!!

The math I posted is for DDR memory sticks named with the "PC" ratings. Ex: PC1600, 2100, 2700....etc. Not SDRAM. SDRAM sticks are rated by the actual name of the stick itself. PC133 = 133Mhz, PC100 = 100Mhz..and so on. If you divide 1600 by 8, you get a Mhz rating of 200...2100 is 266, 2700 is 333, 3200 is 400mhz. That is so you can match your memory type, to the FSB ratings of your CPU.

Now, as far as motherboard support goes however, that's dependent on the chipset. The chipset's support ratings will allow you a given choice of processors you can use.

Yes, and No...from a certain point of view. (depends on how one looks at that question) The memory you can use on a given motherboard is determined by the chipset. For optimal performance, you should match up the memory you buy, with the CPU that's going to be used on that board.

For example: If you're using an AMD XP 3000+ processor, with a 333mhz FSB, your best bet is to either purchase PC2700, or PC3200. The PC2700 will run at it's native speed of 333, and if you install the PC3200 such as I have, you can lower the FSB to 333 in the motherboard's BIOS. Then, if you upgraded it to a XP 3200+ with a 400mhz FSB, you simply set the memory to run at 400!

Don't confuse the CPU's rated speed (core clock speed currently rated well into the Ghz range) with it's FSB (Front Side Bus currently rated in the Mhz) speed. The core clock speed is how fast the CPU processes data. The FSB speed is how fast the CPU communicates with the system. Like this:

CPU talks to the North Bridge. North Bridge is directly connected to the South Bridge, the memory chips (memory controller), and the AGP slot (or PCI-E (video card)). Everything else is directly connected to the South Bridge. Your CD/DVD drives, your PCI cards, your system's sound (onboard, or PCI) your hard drives...USB..floppy drive, etc,etc. **

Each of those systems run on a set frequency...or Mhz rating.


If you want advice on what to buy, my only suggestion is this: What do you want your system to do?

Then, that will determine what you need to buy to support that. Get yourself a motherboard that has upgrading potential. In my case, I also opted for the faster memory chips, so that if I chose to upgrade the CPU, I wouldn't have purchase faster memory.

If you're choosing to go the route of 64bit CPUs...I would suggest an Abit, or Asus Socket 939. Those boards support single, as well as dual core CPUs...with tons of upgrading potential. Lots of support for multiple types of drives both ATA, and SATA...PCI-E graphics and SLI configs...you name it. Along with massive PC3200 support up to 4Gigs of system memory.

Again, sorry for the confusion.

**Note: Just so you're not totally lost, the AMD 64bit CPU's no longer use the North Bridge as it's memory controller...they all have their's built into the CPU. Which means the memory controller runs at the same speed as the core. So, if you bought an AMD64 running at 2.2Ghz, the memory controller inside is running at 2.2Ghz.

 

Thanks, so with the AMD 64 bit CPU the theoretical FSB speed would be the equivalent of the CPU speed? Are these CPU's the best out there? With my HP Pavilion the memory speed is 100 MHz synchronous with maximum 256 MB memory. Would this mean my FSB is 100 MHz? They told me my FSB speed is 133 MHz. So, even though I have a 64 MB SDRAM and 256 MB RAM occupying the two DIMM sockets, it cant run at greater than 256 because this is the maximum right? So I take it that 100 MHz is very lame? Are the memory chips (controllers) the same as the chipset? I have an Intel 810 Chipset. So if I buy a computer with "fast" memory chips I wont have to change the memory if I upgrade the CPU? Sorry if Im a little confused, but thanks for your patience and help with this.

 

It's a good thing to learn what you need. However, the computer in question here should be put out to pasture.

Your chipset determines just about everything. If the fastest it can go is 100mhz, then buying 133mhz ram, or cpu with an fsb of 133, will still run at 100. Otherwise, you're running what they call an asychronized system. Can cause bottlenecks, and other issues.

 

Thanks for all your help Morph416!!