Hi to all at Techspot. I'm not a techie but noticed that there was two kinds of memory, DDR3 and DDR5. My Question is,
What's the difference between DDR3 Memory and the Graphics DDR5 Memory and if the DDR5 is in anyway better then why is it not used for desktop computer memory instead of DDR3.
I know some apps are taking advantage of or utilizing graphics memory Thanks for any explanation
Here the details:::::
As a RAM retailer I’m often asked about whether RAM of different speeds are compatible with certain makes and models of computers. I thought it'd be a good idea to write a small tutorial to explain how the different RAM speeds work, maybe this'll help make things clearer. If you find this guide helpful please remember to click the “Yes” button at the bottom – the more people who click that button the more this guide gets pushed up in the rankings, and the more it will be seen by other people.
Before we talk about the RAM speeds I’d like to talk about something else so I can use it as an analogy when we talk about the speeds. You may have noticed that the capacity of your RAM and your hard drives aren’t exactly what they were advertised at. For example, you might have bought 1GB of RAM only to install it and see it come up as 923MB. The memory business allows a 10% margin of error. A 1GB RAM module actually has room for 8,589,934,592 bits of information – that’s 8 Billion memory addresses. As you can imagine, it would be pretty hard to get a 100% score on a test with 8 Billion questions. They allow themselves to get a 90%, or an A grade if you’re in the US school system. If the module is within that 10% margin of error it’s considered good enough to sell.
Now for the speed conversation. Likewise, not all RAM modules can run at the full speed they were built to run at. There are four main groups of RAM technology: SDRAM, DDR1, DDR2, and DDR3. There are a few others, but we don’t need to go into them for the sake of this tutorial. Each of the four groups I mentioned are broken down into a few possible speeds:
SDRAM – 66Mhz, 100Mhz, 133Mhz
DDR1 – 266Mhz, 333Mhz, 400Mhz
DDR2 – 400Mhz, 533Mhz, 677Mhz, 800Mhz
DDR3 – 400Mhz, 533Mhz, 677Mhz, 800Mhz, 933Mhz, 1066Mhz
On each RAM module is a small chip that communicates with your computer. When it’s installed and you turn on your PC the computer asks the RAM “What speed are you?” The little chip replies with whatever information it’s been programmed to reply with. Each module is built with the hope of it being able to reach the maximum speed for its group, and after being built they go through a Quality Assurance test. That little chip is programmed to respond with information based on how high the module scored on it’s QA test, so if it runs at 800Mhz but has a lot of errors, but runs at 677Mhz without errors it'll be programmed to reply, "I'm 677Mhz."
There are a few nice things about this arrangement. First, say the manufacturer builds 5,000 DDR1 modules and 1,000 of them are marked 266Mhz and 1,000 are marked 333Mhz. If the manufacturer gets an order for 2,000 266Mhz modules they don’t have to build 1,000 more modules, they just take 1,000 of the other ones and reprogram that little chip to respond with “I’m 266Mhz”, label them as 266Mhz, and ship them out the door.
Another nice thing is that if you’re building a computer and you know what I’ve just explained then you know that you’re not necessarily restricted to one specific speed of RAM. If your PC uses DDR1 RAM it could possibly use all three speeds of DDR1. That's handy if you've got other RAM laying around. But there are a few considerations that can affect this.
Computer manufacturers plan in advance. Before a single computer was built designed for DDR3 RAM the computer manufacturers and RAM manufacturers sat down and planned everything out. Intel and AMD might not have a processor capable of using the faster RAM speeds yet. Or the motherboard manufacturers might not have built a motherboard capable of handling the faster RAM yet. But they know they’ll have those designed and produced by next year. So in the mean time they needed to figure out a way for the motherboards and CPUs they're building now to talk to each other and agree on what speed they're going to run at so they can use the slower and faster RAM modules.
So say you put together a computer whose CPU and/or motherboard can only run at 333Mhz but you put in RAM that runs at 400mhz. The Motherboard will ask the RAM “What speed are you?” The RAM replies, “I’m 400Mhz.” The motherboard says, “Okay, but we run at 333Mhz, you’ll have to slow down and run at our speed.” The reverse is also true. The Motherboard might be 333Mhz and you put in 266Mhz RAM. Then the motherboard and CPU will slow down to run at 266Mhz.
There are some really old computers – the ones that used SDRAM – that were built differently. The only thing I can think of is that the computer manufacturers didn’t plan things out as well back then, because some of those old computers won’t accept a module that's a different speed than the motherboard. Those PCs seem designed to ask what speed the RAM is and if they didn’t reply correctly the motherboard would stop and report an error. I guess they realized later they could program them to do what I described above. But I’ve never run into this problem with computers that use any of the DDR types of RAM.
So, having read all this you may still be having problems finding RAM that works in your computer. There are two other factors that are commonly talked about when it comes to RAM: chip density and CAS latency. I’ve written a separate guide on chip density, just look at my other guides (they're listed at the bottom of this page). As for CAS latency, I’ll be honest. I’ve been buying and selling RAM for 5 years and I still don’t completely understand what the CAS latency measures – but I can say that I’ve never had a single module of RAM returned that the problem came down to CAS latency. I used to sell both high and Low Density RAM, and when I did 75% of my returns come from people who didn’t read my listing completely and bought the wrong density. The other 25% of my returns came from people who bought a RAM module that was of a higher capacity than their computer could accept.
I guess that’s a good tip I can add in this guide too. If your computer’s specifications say it can handle 2GB of memory and you have 2 expansion slots – chances are your computer cannot use a 2GB module. It will probably only recognize 1GB in each expansion slot, and you’ll have to buy two 1GB modules to reach the 2GB total your computer can use. There are some computers that will accept it all in one expansion slot, but the overwhelming majority of them require you to use both slots. So if you really want to make sure your computer will be able to use the RAM, buy half the total possible for the computer and install that in each slot.
