Newbie; Low or High Density ?

[oakmead]

Hello, newbie here with limited knowledge in regard to pc upgrading, however, I'm attempting to resurrected an old pc.

It's a Pentium 4, 3.00ghz Prescott (supports 64bit), currently has 512mb pc3200 DDR RAM and running Windows XP.

I only plan to upgrade RAM and maybe install Windows 7.

Motherboard is a Asus P8P500se.

I intend to purchase matching pairs of 2x1gb pc3200 RAM from ebay.

The Motherboard User Manual states it supports 1gb DDR RAM modules but fails to mention whether it supports Low Density RAM.

I read that Low Density Ram is specifically for Intel chipsets and compatible with 100% of Motherboards.... ?

Therefore, am I best sourcing Low Density RAM or do I have no choice as it's the only RAM I can use ?

Is it best to source RAM with a Latency of 2.5 or is this less important due to age of pc and should I stick with CL3 ?

I'm also confused in regard to Memory results of CPU-z; it state 2 channels for my memory and one reads 166mhz and the other 200mhz.

Firstly, why two channel readings displayed and why both not running at 200mhz; it's DDR 400mhz after all ?

I apologise for so many questions within a first post but I did searched the Internet for such answers before posting.

 

[brispuss]

Could not find the motherboard model P8P500SE(?)

Is the motherboard model supposed to be P5P800 SE? If so, the motherboard supports (as per manual on page 2-13) 128 MB, 256 MB, 512 MB, and 1 GB density DIMM's.

CAS 2.5 is preferred over CAS 3, as the memory works a bit faster. But it is not critical, as there is little difference in actual performance.

Using CPU-Z, and selecting the Memory tab, shows the present memory clock frequency. The DDR DIMM's run at TWO times this clock frequency.

Selecting the SPD tab in CPU-Z shows available operating frequencies of the DDR memory, it does not show the current or present operating frequency of the DDR memory.

 

[oakmead]

Yes, the motherboard is the P5P800 se; I typed from memory, sorry.
Thanks for your perseverance.

I see the supported memory listed on page 2-13 of the User Manual but I fail to see where it states low of high density ?

Your reply, which I'm grateful for, reiterates what's stated within the User Manual and you add the the word " density " but fail to say whether high or low; am I missing something ?

Does the terminology, such as 128 MB, 256 MB and so on denote the density, if so which ?

As for CPU-z: under memory, the memory is running at 200mhz, my confusion is on the SPD tab as it shows two channels; one channel running at 166mhz and the other at 200mhz.

I believe there's only one 512 MB pc3200 memory stick in my pc, so why not one channel for one memory stick and the one frequency reading at 200mhz.

Or does one memory stick consist of two banks of chips, thus the two channel readings displayed in CPU-z; and the 166mhz reading is the remaining frequency of one bank of chips ?

 

[brispuss]

Density of memory is measured in Mb (Mega bits), Gb (Giga bits), MB (Mega Bytes), or GB (Giga Bytes). Therefore, the 128 MB module is the lowest density of the compatible modules, while the 1 GB module is the highest density of compatible modules. Sometimes the word "Capacity" is used instead of "Density" to describe memory module 'rating', but "Density" is the more appropriate term. Often the word "Density" is left out, as per the user manual, but the word is taken to be implied.

The SPD tab in CPU-Z only shows what frequencies (and corresponding timings) are available for the memory module. It does NOT show what frequency the module is running at present.

The Memory tab in CPU-Z shows the frequency (and corresponding timings) the module is running at presently. The module can only run at ONE frequency setting, it can't run at two or more frequencies simultaneously. And the number of chip banks has nothing to do with frequency of module operation.

 

[oakmead]

I appreciate the time taken to compose such a detailed reply, however, I may be going out on a limb here; but I believe your understanding of High and Low Density Memory is wrong.

The following links below show pc3200 DDR RAM; both consisting of 1gb memory module or more and both described as Low Density.

https://www.txmicro.com/1GB-PC3200-DDR-400mhz-Dimm-Low-Density-DDR-Memory-Ram-p-4572.html

http://www.dr-memory.co.uk/memory/154-low-density-2gb2x1gb-ddr-400-pc-3200u-non-ecc-desktop-pc-memory-ram-184-pin.html

My understanding of the Density of memory modules is their construction;

1 gb Low Density module contains 64M×8 chips.

1 gb High Density module contains 128M×4 chips.


The more I investigate, it appears High Density Memory is of the snide none branded/labelled variety and should be avoided.

Therefore, Motherboard manufactures expect Low Density memory modules to be used within their products at all times, thus that is to the reason why it's not mentioned within my Motherboards User Manual.

I've also read elsewhere and I mentioned this earlier, that Low Density Memory is compatible with 100% of Motherboards.


As for the CPU-z SPD tab; I have two columns which I refereed to previously as channels, these columns are labelled as:

JEDEC#1

Frequency: 166mhz
CAS# Latency: 2.0
RAS# to CAS#: 3
RAS# Precharge:3
tRAS: 5
tRC: EMPTY
Command Rate Greyed out
Voltage:2.50v

JEDEC#2

Frequency: 200mhz
CAS# Latency: 2.5
RAS# to CAS#: 3
RAS# Precharge:3
tRAS: 6
tRC: EMPTY
Command Rate Greyed out
Voltage:2.50v

I still have no idea, yet, as to what any other these readings mean but as my current memory is 1 x 512mb pc3200 DDR 400, I expected to see only one column with readings displayed and a frequency of 200mhz due to the pc3200 memory module installed.

 

[brispuss]

The Density is the total capacity of the (chips), which is usually denoted in Gb (Giga bits). The equivalent in Giga Bytes (or in Mega Bytes = MB) is Giga bits/8 = GB. So a chip with 1 Gb Density = 1 Gb/8 = 128 MB Density.

Density values alone do not indicate chip architecture (architecture such as 128M x 8, for example).

Low Density chips are often designated due to 4 bit width used in the memory chip architecture, and High Density chips are designated due to use of 16 bit width in memory chip architecture. Standard Density chips would use 8 bit width. All of this is usually quoted.

However, my interpretation of "Low" and "High" Density basically relates to the total Density of chips used and not to the architecture used to create the total Density. A memory module may use 256Mb chips, or 512Mb chips, or 1Gb chips etc. The 256Mb chip would be considered low Density (relatively).

Regardless of how High and Low Density memory is interpreted, memory compatibility is a function of several factors, amongst them chip architecture. Some chipsets/CPU's may not recognize, for example 128M x 4 architecture, but may recognize 64M x 8 architecture, despite both chip architectures totaling 1 Gb Density. It is the chip architecture which is more important than the Density per se. Unfortunately, many motherboards do not clearly specify what architectures are supported. That is when reference to datasheets (if available) for chipsets and CPU's are required to determine memory compatibility (based on memory chip architecture).

Also, unfortunately, many memory manufacturers do not indicate details of memory chips used in the modules, so it is difficult to determine whether the memory is Low or High Density. However, to get around this, most memory manufacturers offer Memory Configurators or Memory Search functions to find compatible memory for the motherboard/system being considered. This maybe the best way to determine compatible memory as memory chip architecture details are usually not readily available.

CPU-Z SPD tab does NOT indicate channels of memory. It just shows what speeds the memory is capable of running, nothing more.

The CPU-Z Memory tab shows the actual/current operating speed of the memory, which in this case is 200 MHz (400 MHz DDR). So this memory is NOT currently running at 166 MHz (333 MHz DDR), as the memory can only run at 166 MHz OR at 200 MHz, it does NOT run at both frequencies at once.

 

[oakmead]

Well yet again, such a fabulous explanation, however the detail expressed is being lost in translation. I really appreciated your reply and I thank you.

All my comments in regard to High and Low Density memory are only what I've have picked up within the last few days, prior to that I wasn't even aware of such differences.

However, I still cant help be feel that your opinion of it appears to contradict what I'm reading elsewhere.

I have since noticed that the DDR400 Qualified Vendors list within the User Manual states the 1gb memory modules which are recommended/supported; I didn't notice this initially as they are listed as 1024mb; I was also viewing it via my mobile phone.

I will ensure to source only the 1gb memory modules which are stated within Qualified Vendors list.

Thanks again for your very thorough explanations.

 

[Pinhedd]

Low Density chips are often designated due to 4 bit width used in the memory chip architecture, and High Density chips are designated due to use of 16 bit width in memory chip architecture. Standard Density chips would use 8 bit width. All of this is usually quoted.

That has nothing to do with it.

High-density vs Low-density is purely subjective and may change over time.

Certain older DDR3 chipsets (Intel 5 series and older) are not compatible with native "high density" 4-gigabit DDR3 SDRAM chips. Similarly, only enterprise chipsets are compatible with stacked FBGA 8-gigabit DDR3 SDRAM chips unless the motherboard manufacturer modifies the MRC in the firmware. Only Intel 6 series and newer support 4-gigabit chips properly when using reference MRC.

SDRAM chips of a given density are usually available in 4-bit, 8-bit, and 16-bit IO-interfaces. Chips of a given IO-interface are concatenated to form a 64-bit rank. The use of 4-bit chips enables twice the rank-capacity for a given SDRAM density compared to 8-bit chips of the same density, but they generally have to be used along with a register to buffer the signals.

 

[brispuss]

Low Density chips are often designated due to 4 bit width used in the memory chip architecture, and High Density chips are designated due to use of 16 bit width in memory chip architecture. Standard Density chips would use 8 bit width. All of this is usually quoted.

That has nothing to do with it.

High-density vs Low-density is purely subjective and may change over time.

Certain older DDR3 chipsets (Intel 5 series and older) are not compatible with native "high density" 4-gigabit DDR3 SDRAM chips. Similarly, only enterprise chipsets are compatible with stacked FBGA 8-gigabit DDR3 SDRAM chips unless the motherboard manufacturer modifies the MRC in the firmware. Only Intel 6 series and newer support 4-gigabit chips properly when using reference MRC.

SDRAM chips of a given density are usually available in 4-bit, 8-bit, and 16-bit IO-interfaces. Chips of a given IO-interface are concatenated to form a 64-bit rank. The use of 4-bit chips enables twice the rank-capacity for a given SDRAM density compared to 8-bit chips of the same density, but they generally have to be used along with a register to buffer the signals.

That information was obtained from various online sources which related memory chip data width to the density of the chips and modules.

As stated previously, my interpretation of high and low density chips is based on total density of the memory chips, and not on chip data width.