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High Density Vs. Low Density Ram

 
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Dino1956
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PostPosted: Mon Dec 29, 2008 4:37 pm    Post subject: High Density Vs. Low Density Ram Reply with quote

I'm guessing the reason the 2 -512 MB PC133 sticks of ram I bought on ebay do not work on my iMac G3, is because they are High Density.

"LOW DENSITY modules have 100% compatibility with ALL systems and ALL chipsets.
HIGH DENSITY modules only have 10% compatibility and are VERY SLOW.
This is also why almost all Branded-Name systems such as Apple/MAC, Compaq/HP, Dell and IBM only uses LOW DENSITY modules.
However 90% of eBay are plagued with High-Density 1GB modules at very low price, and you will be wasting your precious time and money having to return those high density 1GB modules to your seller for refund. So AVOID those 'High-Density - 128Mx4 config' 1GB modules which is usually UNBRANDED and is NO NAME!"

I knew there had to be a catch ! When it's too good to be true, it usually always is.
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Dino1956
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PostPosted: Fri Jan 02, 2009 10:16 pm    Post subject: Reply with quote

I have a Question:

What computers can you use High Density Ram for ? I tried a Dell, Hp & my iMac. It seems to me High Density is not compatible with any Computers ? So why did they manufacture it in the first place ?

It truly doesn't make ANY sense to me, why it even exists!
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saul
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PostPosted: Fri Jan 02, 2009 11:11 pm    Post subject: Reply with quote

It's all about money. High density memory usually works in motherboards with older chipsets that have been tweaked to work with the cheaper memory so the clone makers can use cheaper components. Also can work in "last of a generation" mainstream boxes - e.g. I had some Compaq PCs at work and high density would work in the newest ones only.

High density memory is basically a process where new chips are put in a DIMM package that they were never designed for. Then someone figures out how to use the cheap memory.
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Dino1956
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PostPosted: Fri Jan 02, 2009 11:27 pm    Post subject: Reply with quote

Well excuse my Italian but THAT SUCKS! Big Time! I haven't had to buy much ram in my Life, but now I know, never to be persuaded by a Cheap Price Tag! Thanks for the explanation.
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hwojtek
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PostPosted: Sat Jan 03, 2009 5:45 am    Post subject: Reply with quote

Dino1956 wrote:
seems to me High Density is not compatible with any Computers?


Early VIA Apollo Pro Pentium II chipsets use this memory. This chipset was about 1/2 cheaper than any competition.
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Dino1956
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PostPosted: Sat Jan 03, 2009 9:19 am    Post subject: Reply with quote

thanks for the tip. Unfortunately I have no P2's lying around except for an old Dell Laptop. This is Desktop Ram. I tried it in a Dell P3, but it did not work. Also in an HP Intel Celeron, no luck with that either.
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Dino1956
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PostPosted: Sat Jan 03, 2009 9:21 am    Post subject: Reply with quote

I wish i could use it for something because by the time I ship it back & they won't refund shipping when they sent it, it's almost the cost of the ram.Smile
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sd2007
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PostPosted: Mon Feb 16, 2009 7:38 pm    Post subject: low density vs. high density RAM Reply with quote

Anyone know how to tell the difference by looking at the ram sticks?
thanks!
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Dino1956
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PostPosted: Mon Feb 16, 2009 9:24 pm    Post subject: Reply with quote

One excerpt from eBay on a 1 GB Stick:

How to tell if your 1GB module is a low or high density module?

All low density 1GB modules are made with 16 chips (8 chips on each side) using 64Mx8 device.
All high density 1GB modules are made with 16 chips (8 chips on each side) using 128Mx4 device.
It costs memory manufacturers almost the same to produce Low Density 1GB modules which have 100% compatibility with all systems on the market, comparing to producing high density 1GB modules. So why would manufacturers be so foolish to produce high density 1GB modules which only have 10% compatibility with systems on the market? The reason is simple, because high density 128Mx4 devices are mainly designed for used in slower server chipset/segment (Registered) which are not designed for PC chipset/segment (Unbuffered).

JEDEC standard/guideline specifies that 64Mx8 and 32Mx16 devices are to be used to construct a 1GB Unbuffered module. Any 1GB Unbuffered module constructed by using 128Mx4 device BREAKS all the JEDEC standard/guideline in which is supposed to be designed only for Registered module. Since JEDEC doesn't want the modules to be built that way, so the companies who make them (a lot are generic and 3rd parties), don't put their company label on the Unbuffered modules.

Due to unusability and high incompatibility of high density modules with standard PC, they are FAR CHEAPER, usually about half the price when compare with low density modules and a lot of buyers have fallen into attractive CHEAP PRICE trap by High Density module sellers and have complained that they will not run at all and sellers would not accept return!

High Density module is also by far slower than Low Density module at same speed rating say PC3200/DDR400.

In summary:-

LOW DENSITY modules have 100% compatibility with ALL systems and ALL chipsets as it fully follows JEDEC guidelines.
HIGH DENSITY modules only have 10% compatibility and are VERY SLOW as it breaks all JEDEC guidelines.
This is also why almost all Branded-Name systems such as Apple/MAC, Compaq/HP, Dell and IBM only uses LOW DENSITY modules.
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iMac 27" 3.06 8GB ATI 4670 1TB HD
Mac Mini 1.83 Intel Core 2 Duo 4GB 80 GB
Macbook Pro 2.4 GHz i5 8 GB Ram 500 GB HD
Power Mac G5 1.8 GHz
Apple TV 3rd Gen
Time Capsule 1st Gen 2TB

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