RAM Indexed guide?

[mikehende]

Ok guys, back on the ball today, I am trying to create a sort of an indexed version or quick reference guide of the RAM chapter, please have a look and tell me if there is anything here that is either missing or needs to be added as some of this stuff was not in the book, this is a combination of what's in the book and my own research on the net, therefore, what I would like to know in particular is, what's in here that will NOT come on the exam and what is missing that will come on the exam?
Please see next post, thanks.

[mikehende]

Types of RAM Chips/Technology:

01] DRAM [Dynamic RAM]
-Needs to be refreshed so it's slow

02] SRAM [Static RAM]
-Faster, does not need to be refreshed. [Loses
data when power is turned off].


03] NVRAM [Non-volatile RAM]
-Differs from both DRAM and SRAM in that it retains
memory when power is turned off.

04] SDRAM [Synchronous Dynamic Ram]
-Memory speed is synchronized with the clock pulse
from the CPU.
-Synchronization enables SDRAM to PIPELINE read
and write requests.
-Pipelining enables SDRAM to accept commands at
the same time as it is processing other
commands.

05] SDR SDRAM [Single Data Rate]
-Original SDRAM standard, replaced by DDR SDRAM.

06] DDR SDRAM [Double Data Rate]
-Doubles the bandwidth of SDR SDRAM by
transferring data twice per cycle on both edges of
the clock signal.

07] DDR2 SDRAM [2nd generation of DDR SDRAM]
-Improves on DDR SDRAM by using differential
signalling and lower voltages to support
significant performance advantages over DDR
SDRAM.

08] RDRAM [Rambus DRAM]
-Developed by Rambus Inc.

09] EDO RAM [Extended Data Out]
-Needed to be refreshed much less often than FPM
but still slow.

10] SPD [Serial Presence Detect]
-Little chip installed on DIMM stick which provides
the system with all of the details about the DIMM
[size, speed and other more technical info].

11] ECC [Error Correction Code]
-Used in higher end systems, better than Parity.
-Most common in 168-pin DIMMS but must work
with MB designed to use it.

12] Registered DRAM
-Facilitates high-volume data flow in and out of
RAM, used in Servers and high-end workstations.

Types of sticks:

1] DIPPS [Dual Inline Pin Package]
-Very early DRAM chip which connected directly to
the MB via 2 rows of pins on either side.

2] SIPP [Single Inline Pin Package]
-First popular stick with onboard DRAM chips->30-pin

3] SIMM [Single Inline Memory Module]
2 Types:
a] 30-pin [8-bit data bus]-Made with contacts [not pins] to
prevent breakage.

b] 72-pin [32-bit data bus]

**When upgrading SIMMS, be sure to check for compatibility
before purchasing.

4] Parity chip->form of error-checking chip in an extra
1-bit chip on stick.

5] FPM RAM [Fast Page Mode]
-DRAM used for the first ten years in the PC industry
and did not use a clock.


6] DIMM [Dual Inline Memory Module]
-64-bit data bus.
-Dimm with 72 contacts will have 36 contacts on
each side.

**Comes in different sizes:
72-SODIMM
144-SODIMM
168-SDRAM
184-DDR SDRAM
240-DDR2 SDRAM

7] SODIMM [Small Outline DIMM]
-For use in Notebooks.

**Comes in different sizes:
72->32-bit databus
144->64-bit databus
200->72-bit databus

[mikehende]

is RIMM a "physical" chip or "part" of a chip or how can it best be explained?

[kern]

Ok guys, back on the ball today, I am trying to create a sort of an indexed version or quick reference guide of the RAM chapter, please have a look and tell me if there is anything here that is either missing or needs to be added as some of this stuff was not in the book, this is a combination of what's in the book and my own research on the net, therefore, what I would like to know in particular is, what's in here that will NOT come on the exam and what is missing that will come on the exam?
Please see next post, thanks.

fwiw Meyers book has all the info you need to know for the tests.

[mikehende]

Yes, I am being told that same thing by most Kern but I still have to go outside the book to organize/categorize certain things and also to get better explanations for some stuff that's not clear to me like the RIMM question I am asking about now.

[kern]

is RIMM a "physical" chip or "part" of a chip or how can it best be explained?

RIMM is a 184 pin memory module, similar to a 168 pin DIMM.

[mikehende]

so it is not a memory "stick"? If so, where on the motherboard is it installed?

[kern]

so it is not a memory "stick"? If so, where on the motherboard is it installed?


it is a memory stick (aka memory module), similar to a SDRAM DIMM.
RIMM = Rambus Inline Memory Module
DIMM = Double Inline Memory Module

[mikehende]

That word "module" was what was throwing me all this time, thanks for confirming Kern so now I will go modify the guide.

Next question [surprised?] anyone, I tried the MEMTEST but this takes a while to give results and I do understand that this gives "thorough" results but what happens if you go to someone's home to check their memory so you don't have all that time to wait for results? Do you have some other utility that can tell you quickly if the memory is fault-free?

[mylanta]

That word "module" was what was throwing me all this time, thanks for confirming Kern so now I will go modify the guide.

Next question [surprised?] anyone, I tried the MEMTEST but this takes a while to give results and I do understand that this gives "thorough" results but what happens if you go to someone's home to check their memory so you don't have all that time to wait for results? Do you have some other utility that can tell you quickly if the memory is fault-free?

Not really and that is the best but I would never try to do something like that in an in-hoe service call anyway. That should be done on a bench.

[kern]

That word "module" was what was throwing me all this time, thanks for confirming Kern so now I will go modify the guide.

Next question [surprised?] anyone, I tried the MEMTEST but this takes a while to give results and I do understand that this gives "thorough" results but what happens if you go to someone's home to check their memory so you don't have all that time to wait for results? Do you have some other utility that can tell you quickly if the memory is fault-free?


other than a hardware memory tester, not really. some ram testers have a "quick mode", docmememory comes to mind, but "burnt-in mode" is more reliable.

[dbarrow]

An "obvious" problem with ram, such as a bad stick or socket, will start to throw errors very quickly in Memtest and Prime95. A faulty stick will show up rapidly. Errors will appear as soon as it hits the bad bank.

The more subtle problems, like a lowered OC timing, make take 24 hrs to show a pattern of errors and dropped data.
The tools are primarily used to test out your OC settings for stability as some overclocks may run but eventually start dropping data which, over time, leads to corrupted files and crashes. Stress testing 24-48hrs for overclocks is strongly recommended.

One of the quickest tests, when first encountering the machine, is to make sure POST ram testing is on in BIOS and the mobo runs it on startup (many BIOS have a setting and/or default to skip the ram test to speed booting. Go through BIOS options and turn it on, usually located in the BOOTUP section)
When you boot the machine again, the POST should report the correct amount of ram and any glaring errors.

The next tool would be Everest and even System Information (in XP) and look at the ram. Is it reporting correct size and information, such as SPD timings, correct voltage, correct FSB?

Don't forget to boot and go into BIOS and take a close look at all settings. You never know what (the user) has been tinkering with in there and they won't (of course) admit to it!

[mikehende]

One of the quickest tests, when first encountering the machine, is to make sure POST ram testing is on in BIOS and the mobo runs it on startup (many BIOS have a setting and/or default to skip the ram test to speed booting. Go through BIOS options and turn it on, usually located in the BOOTUP section)
When you boot the machine again, the POST should report the correct amount of ram and any glaring errors.

The next tool would be Everest and even System Information (in XP) and look at the ram. Is it reporting correct size and information, such as SPD timings, correct voltage, correct FSB?
!

I don't see a specific "boot up" section in the BIOS, only "Boot Sequence" and don't see any mention of RAM in there? Also looked at at System in the Control Panel and nothing their either?

[dbarrow]

Depending on the mobo and the BIOS, there is usually some advanced boot options like quick boot, splash screen, etc.
Mobos used to run a ram check as part of the POST as a default. In many of the newer BIOS, there is an option to turn that off. When it first starts to boot, you see numbers running up on the screen, that is the ram check until it gets to the top = size of installed ram. Then it moves on to detecting the drives.
If the mobo detects a bad checksum as it does this, it will usually beep or reboot into BIOS setup.

System Information is in System Tools
Shows lots of interesting information
Does not detail your ram

Everest home edition\motherboard section details your ram

[mikehende]

In many of the newer BIOS, there is an option to turn that off. When it first starts to boot, you see numbers running up on the screen, that is the ram check until it gets to the top = size of installed ram. Then it moves on to detecting the drives.

System Information is in System Tools
Shows lots of interesting information
Does not detail your ram



That's very strange, with my old PII Test pc this is the case but in my newer pc, you don't see the POST.

I had completely forgotten about the System Info under system Tools, thanks for the reminder.

[dbarrow]

I bet if you dig deep enough you will find a setting(s) to enable Power On Self Test functions including memory check.

I think most of the newer ones, being much stable now, default it to off or "Quick Boot" which skips it.
I know that was the case on daughter's machine when I flashed the new BIOS and wanted to tinker with the OC settings. I had to enable it in the Bootup options in a sub-menu.

[mikehende]

Ram question, is 512mb SDRam equivalent to 256 DDR2SDRAM?

[mylanta]

Ram question, is 512mb SDRam equivalent to 256 DDR2SDRAM?
In theory it would be the same as Ddr...but in practice no...it is a lot faster and let's leave it at that.

[mikehende]

it is a lot faster and let's leave it at that.
Alright Rich, don't wish to open up a can of worms huh?:) Thanks.