Is low density RAM faster than high density RAM?
- Thread starter ADE
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Higher density has more to do with capacity then speed depending on type. The first cd-rs were only 60min. in length for audio tracks. The next generation was the slightly higher 74min. cd-rs soon to be replaced by the 80min. disks commonly used.
A double density floppy was 2.88mb instead of 1.44mb. When selecting memory you have to go by the type or types supported. Again some boards won't support a 1gb dimm which is a higher density then a 512mb although they are the same size. Memory frequency speed and CAS latency controls which memory is faster. DDR400 at 400mhz is faster then DDR333 at 333mhz. DDR400 with a lower set of timings like 2-2-5-2 is faster then the typical 3-3-3-8.
A double density floppy was 2.88mb instead of 1.44mb. When selecting memory you have to go by the type or types supported. Again some boards won't support a 1gb dimm which is a higher density then a 512mb although they are the same size. Memory frequency speed and CAS latency controls which memory is faster. DDR400 at 400mhz is faster then DDR333 at 333mhz. DDR400 with a lower set of timings like 2-2-5-2 is faster then the typical 3-3-3-8.
Motoxrdude
Active Member
Is it like single sided ram and doubled sided ram?
It's school time kiddies! 
How about some basic facts!
Types of RAM
RAM comes in different types and flavors to suit different needs and budgets. There are many specialized types of RAM, but some of the more common types are:
What type of RAM Should I Choose?
You must decide what type of RAM your homebuilt computer will use before you buy a motherboard. This is because most motherboards are able to use only one type of RAM.
Ordinary SDRAM is rapidly becoming obsolete. So if you are building a new computer, chances are you will be deciding between DDR-SDRAM or RAMBUS.
Unless you are building a computer that will require truly massive speed (even beyond that required by all but the most high-pressure gaming applications), we suggest that you use DDR-SDRAM. It's fast, stable, and relatively cheap.
DDR-SDRAM can also be installed in dual-channel configuration, if your motherboard supports it. When using dual-channel DDR, pairs of identical RAM modules work in tandem to greatly improve performance. Both the size and the speed (and preferably, the manufacturer, in our experience) of each RAM module in a dual-channel pair must be identical.
If you want the absolutely fastest RAM available, then look into RAMBUS. But be prepared to spend several hundred dollars on RAM alone. Like dual-channel DDR, RAMBUS modules must be installed in identical pairs.
How Much RAM do I Need?
Dollar for dollar, nothing will liven up your homebuilt computer more than endowing it with a respectable amount of RAM. In addition, because RAM is so central to your computer's functioning, always choose RAM made by a reputable manufacturer like Crucial.
Every operating system has "minimum system requirements" for processor speed and RAM; but in our experience, the minimum requirements tend to be grossly inadequate if you actually want the computer to do anything useful. Instead, we suggest the following RAM amounts for optimal performance of desktop PC's running the following popular operating systems:
There does come a point when you are not likely to see any noticeable improvement by adding more RAM. Going very much above the higher figures in the table above is not likely to improve your computer's performance in any noticeable way. And of course, you cannot install more RAM than your motherboard can support; so make sure you know this figure before buying up every last stick of RAM in the store!
RAM Speed
The speed of RAM you will need depends mainly on the motherboard. You generally should choose the highest speed of RAM that the motherboard supports. Make sure that you check the motherboard documentation to find this out. Just because a stick of RAM fits in a motherboard doesn't mean it will work. Sometimes, inserting the wrong RAM and powering up the mobo can damage the board, the RAM, or both.
Even if your motherboard can support different RAM speeds, using slower RAM than the fastest that the mobo supports means you won't get the maximum performance that the board is capable of delivering.
As the speed capabilities of RAM of a given type improve, newer, faster RAM is usually backward-compatible to slower speeds. This is accomplished through the use of a serial presence detection circuit built into the RAM module. So for example, most PC-2700 (333 MHz) DDR-SDRAM sticks are backward-compatible to PC-2100 (266 MHz). So if your board is built for PC-2100, but you can get PC-2700 for the same price, you may as well go for the faster RAM. You never know: You may want to use it in your next project. (Just make sure that the RAM you buy is backward-compatible to the speed you need now!)
The one thing you generally should avoid, however, is mixing RAM speeds in the same computer. In theory, if you mix RAM speeds, all of the modules should clock to the lowest speed; but in practice, mixing speeds (and sometimes even brands) in the same PC can cause system instability. (And of course, RAMBUS and dual-channel DDR must use matched pairs of identical modules.) http://www.kitchentablecomputers.com/ram1.htm
How about some basic facts!Types of RAM
RAM comes in different types and flavors to suit different needs and budgets. There are many specialized types of RAM, but some of the more common types are:
- SRAM. Static Random Access Memory is very fast and very expensive. It is primarily used for memory caching (such as on processor chips). Architecturally, it has multiple transistors for each memory cell. It does not need to be refreshed.
- DRAM. Dynamic Random Access Memory is slower than SRAM and needs to be refreshed many times every second. Each memory cell consists of a capacitor and a transistor. DRAM is much less expensive than SRAM.
- SDRAM. Synchronous Dynamic Random Access Memory is a special type of DRAM that is synchronized to the system clock. Each chip contains internal registers that accept requests from the CPU, thus freeing the cpu to do other things while the data is assembled. Since SDRAM is synchronized to the CPU, it "knows" when the next cycle is coming, and has the data ready when the CPU requests it. This increases efficiency by reducing CPU wait states. SDRAM is available at speeds as high as 133 MHz.
- DDR-SDRAM. Double-Data Rate SDRAM works the same way as does ordinary SDRAM, except it works twice as quickly by synchronizing to both the rising and falling of the clock pulse (which makes it twice as fast as ordinary SDRAM). DDR-SDRAM can also be installed in dual-channels if the motherboard supports this arrangement. There is no difference in the actual RAM modules used for dual-channel DDR, but the two sticks of RAM in each channel must be a matched pair (same size and speed).
- RDRAM. Rambus Dynamic Random Access Memory is a very fast type of RAM in which the chips work in parallel to produce very fast speeds. However, because it is proprietary and very expensive, RDRAM has been slow in catching on.
What type of RAM Should I Choose?
You must decide what type of RAM your homebuilt computer will use before you buy a motherboard. This is because most motherboards are able to use only one type of RAM.
Ordinary SDRAM is rapidly becoming obsolete. So if you are building a new computer, chances are you will be deciding between DDR-SDRAM or RAMBUS.
Unless you are building a computer that will require truly massive speed (even beyond that required by all but the most high-pressure gaming applications), we suggest that you use DDR-SDRAM. It's fast, stable, and relatively cheap.
DDR-SDRAM can also be installed in dual-channel configuration, if your motherboard supports it. When using dual-channel DDR, pairs of identical RAM modules work in tandem to greatly improve performance. Both the size and the speed (and preferably, the manufacturer, in our experience) of each RAM module in a dual-channel pair must be identical.
If you want the absolutely fastest RAM available, then look into RAMBUS. But be prepared to spend several hundred dollars on RAM alone. Like dual-channel DDR, RAMBUS modules must be installed in identical pairs.
How Much RAM do I Need?
Dollar for dollar, nothing will liven up your homebuilt computer more than endowing it with a respectable amount of RAM. In addition, because RAM is so central to your computer's functioning, always choose RAM made by a reputable manufacturer like Crucial.
Every operating system has "minimum system requirements" for processor speed and RAM; but in our experience, the minimum requirements tend to be grossly inadequate if you actually want the computer to do anything useful. Instead, we suggest the following RAM amounts for optimal performance of desktop PC's running the following popular operating systems:
Windows 98/Me: 256 - 512 MB
Windows 2000/XP: 512 - 1024 MB
Linux (kernel 2.2 with x-server): 256 - 512 MB
Linux (kernel 2.4 or 2.6 with x-server): 512 - 1024 MB
Linspire (formerly Lindows): 512 - 1024 MB
If you use your computer for graphics manipulation, video editing, TV or DVD viewing, gaming, CAD/CAM applications, or complex mathematics, then you should lean toward the higher numbers. If you mainly use it for email, web surfing, and office apps, than the lower numbers should be sufficient. Windows 2000/XP: 512 - 1024 MB
Linux (kernel 2.2 with x-server): 256 - 512 MB
Linux (kernel 2.4 or 2.6 with x-server): 512 - 1024 MB
Linspire (formerly Lindows): 512 - 1024 MB
There does come a point when you are not likely to see any noticeable improvement by adding more RAM. Going very much above the higher figures in the table above is not likely to improve your computer's performance in any noticeable way. And of course, you cannot install more RAM than your motherboard can support; so make sure you know this figure before buying up every last stick of RAM in the store!
RAM Speed
The speed of RAM you will need depends mainly on the motherboard. You generally should choose the highest speed of RAM that the motherboard supports. Make sure that you check the motherboard documentation to find this out. Just because a stick of RAM fits in a motherboard doesn't mean it will work. Sometimes, inserting the wrong RAM and powering up the mobo can damage the board, the RAM, or both.
Even if your motherboard can support different RAM speeds, using slower RAM than the fastest that the mobo supports means you won't get the maximum performance that the board is capable of delivering.
As the speed capabilities of RAM of a given type improve, newer, faster RAM is usually backward-compatible to slower speeds. This is accomplished through the use of a serial presence detection circuit built into the RAM module. So for example, most PC-2700 (333 MHz) DDR-SDRAM sticks are backward-compatible to PC-2100 (266 MHz). So if your board is built for PC-2100, but you can get PC-2700 for the same price, you may as well go for the faster RAM. You never know: You may want to use it in your next project. (Just make sure that the RAM you buy is backward-compatible to the speed you need now!)
The one thing you generally should avoid, however, is mixing RAM speeds in the same computer. In theory, if you mix RAM speeds, all of the modules should clock to the lowest speed; but in practice, mixing speeds (and sometimes even brands) in the same PC can cause system instability. (And of course, RAMBUS and dual-channel DDR must use matched pairs of identical modules.) http://www.kitchentablecomputers.com/ram1.htm
What does anything he ever posts have to do with the thread??
http://www.4allmemory.com/index.cfm?fuseaction=faq.details&faq_id=102
http://www.4allmemory.com/index.cfm?fuseaction=faq.details&faq_id=102
Your copy-paste has schooled me. I am learned now
What does that have to do with what high/low density RAM
Besides the difference in capacity seen between various types of memory someone we both know would recommend mixing different sizes together when adding memory to a system.
"two sticks of RAM in each channel must be a matched pair (same size and speed)." You wouldn't want to run two 512s with a single 1gb dimm added now would we?
Yet "someone" would argue that point. 
hhmmmm...What the bloody hell does that have to do with anything???? Holy shit. The guy didn't even specify that he had dual channel, number one. Number two, it doesn't matter a damn what size the modules are if you're not running in dual channel. I guess it does to you, but you've already proven your lack of tech abilities quite amply. I don't seem to have a problem. It isn't exactly rocket science and judging by the sigs here there are a lot of people that would agree.
Show me any memory expert that would agree with you. ANY.
Show me any memory expert that would agree with you. ANY.
Besides the difference in capacity seen between various types of memory someone we both know would recommend mixing different sizes together when adding memory to a system.
"two sticks of RAM in each channel must be a matched pair (same size and speed)." You wouldn't want to run two 512s with a single 1gb dimm added now would we?
This really is all irrelevent to the thread...
As usual someone fails to fully read the article.
hhmmm.... One thing that is even more relevent is the article that explains some points a little more clearly for the late comers since this also explains about density and capacity.The reason is memory density migration relation to compatibility with different computers. When computer manufacturers design and build new computers, they attempt to build in support for all DRAM chip densities that are available at the time. When PC100's were released, only 16MB chips and 64MB chips DRAM densities were available, but at that time, 128MB chips were already in the design phase, so the computer manufacturers built in support for this higher memory density. Today, manufacturers are capable of producing chips with densities of 256MB, 512MB, 1Gb and 2GB chips. As manufacturers get more density, or storage, per chip and migrate to newer processes, the production cost per megabit decreases.
The memory market is dictated by supply and demand. As demand increases for a higher density chip, the demand for older, lower density chips usually declines. Manufacturers typically shift their production accordingly. If the supply of the lower density chips decreases faster than demand, the market price per bit on these chips will remain high in comparison to the newer, higher density chips. That is why for example we can see higher pricing for 128MB SDRAM chips relative to 256MB SDRAM chips. The fact is that the older systems cannot support the newer, higher density, lower cost chips. The computer's chipset can only support the memory technology it was designed with, and the majority of systems out there only support lower density modules. Most users, especially when they are unaware about the importance of chip density and compatibility, will choose the lowest priced memory with specifications that LOOKS to be identical. But there's nothing more frustrating than trying to install your new memory only to find that it doesn't work with your system. http://www.oempcworld.com/support.htm
Anyone still stuck on finding out what memory can be used on their system?
http://configurator.oempcworld.com/index.asp
As usual he can't stay on topic (but I see he loves his cut and paste though)
To stay on topic so hopefully people will just ignore him, new 1GB modules use either 64Mx8 devices for low density, 128Mx8 devices for high density. Both are 16 chip.
Low density is always compatible, high density is 10% compatible. High density chips are rejects that could not be made into low density modules.
It has been brought to my attention that high density modules, while cheaper, can also be slower, but they are not eligible for a return or refund.
So, be careful what you buy.
To stay on topic so hopefully people will just ignore him, new 1GB modules use either 64Mx8 devices for low density, 128Mx8 devices for high density. Both are 16 chip.
Low density is always compatible, high density is 10% compatible. High density chips are rejects that could not be made into low density modules.
It has been brought to my attention that high density modules, while cheaper, can also be slower, but they are not eligible for a return or refund.
So, be careful what you buy.
PC eye, according to your profile you are 51 years old. Isn't it about time you grew up and acted those 51 years instead of pasting some random blurb that has absolutely nothing to do with the question?
I wish I were a copyright lawyer, I could sue your ass into next week with all the copy-and-paste infringement you do.
I wish I were a copyright lawyer, I could sue your ass into next week with all the copy-and-paste infringement you do.