Dumb CF-29 RAM Question

I bought a lot of 4 CF-29, 1.3GHz laptops to rework. They came in with 512MB base RAM and a 512MB stick of off-name RAM.... The weird thing is that it is PC2100 RAM and not PC2700. It seemed to work until I added GPS and made some BIOS updates and tweaks. Then I got a weird 6 column flashing lightshow overtop the blue Windows logon screen. I scratched my head about this for a minute thinking a I may have done something wrong. But it was a stock GPS install... Not a custom job... And I really wouldn't post here if I had actually done something wrong.

So... You techified bunch... I know you can go up the RAM scale to a degree... But can you go back and have the laptop still function at capacity?

 

Whats the question again?
Do you want to know if 512mb will work OK ?

Anyway
I have seen these issues before using pc2100 ram
Its not a simple fail like we used to see in the cf-28's
I have installed pc2100 ram and the toughbook would run fine for a full windows reload and then start acting up after running for a few hours
Stick to pc2700 for reliability in the mk-2's , the mk-1's work fine with pc2100

The toughbook will run fine with only 512mb total with xp
Not too many applications will need more than that
Typical ram usage less that 300mb total with a few applications open c/w antivirus running





Alex

 

Dude... I know HOW much RAM I can put in.... The question was about the use of PC2100... My RAM sites show that it should take PC2700.

But I guess I never did end my story.... I took the PC2100 stick of RAM out and the video issue went away immediately. All 4 1.3GHz laptops have the same type of RAM... A picture of a Viking next to "PC2100 Compliant" is all it shows. I guess I could try looking up all the numbers on it... But the fact is it is not working 100% in these laptops.

 

As I said stick to pc2700 in the mk-2's
I have had the same issues with pc2100 ram BSOD etc
If it was not generic it might of been able to overclock to the pc2700 standard
Pc2100 works great in mk-1's


Alex

 

FWIW, I use a 1GB stick of DDR2 PC2-5300 in my CF-29. So it will work with anything faster than 2700. Anything slower than 2700 will probably cause problems.

 

DDR2 will not work in a 1.3GHz... It it is DDR as is the 1.2GHz model. The 1.4GHz and 1.6GHz are DDR2 models.

 

I was under the impression that the DDR2 upgrade wasnt made till MK4, or are there 1.4ghz MK4s?

 

Nope... The 1.4GHz are DDR2 also...

 

Well, let me throw in my .02. I have seen this problem in other laptops (and desktops) that I built / repaired over the last few years. It seems to happen 99% of the time on computers that use shared memory for the video. For some reason the memory starts to 'leak' and cause all kinds of funny video problems. I have seen it most typically after additional programs after the OS is installed. I also found that it seemed to happen with the 2100ddr and early versions of 2700ddr (although is been quite a while since 2700ddr systems have misbehaved like this). I heard from a good source that it's a memory management/voltage issue. It's not a MB issue as much as a efficiency in the chip issue.

I am not an expert on this, so I am just passing on information and experience. About a year ago I had four customers who's 'video' issues were solved by pulling 2100 and installing 2700.

I guess that was more like .04, but who's really counting???

K1SFD

 

The problem is this;

Most modern laptop chipsets (excluding the more expensive "gaming" or "desktop replacement" models) use shared RAM for their video. Under normal conditions, ANY RAM that is DDR or NEWER, the chipset will adjust RAM timing by SPD, a tiny bit of configuration info stored on the RAM which has been part of the JEDEC standard since the inception of DDR specified RAM.

The problem is this; when the video portion of the chipset addresses this RAM, it addresses it DIRECTLY, at whatever clock speed it needs to depending on the video being shown. While you're doing an OS install, or working in BIOS, you're typically only operating at low resolutions (800x600 or 1024x768) and low color density (8-bit color or 16-bit color) because you're using default VGA video drivers built into Windoze. At those color depths, you'll NEVER overload the capability of the RAM - even PC100 or PC133 can keep up with it.

Once you install the correct video drivers, BAM! Winblows wants to run at 24-bit or even 32-bit color depth; here your data bandwidth usage in video RAM increases in geometric proportion, so the Video Chipset is hammering that tiny bit of your RAM exponentially faster and faster until... it leaks. The interleave is wrong, the CAS/RAS is beyond the limits of the RAM and it just loses its coherence in that area. Sometimes it'll cause a BSOD, other times it'll make some really kewl lightshow fer ya.

So your previous owner popped in some Viking RAM - (Viking, BTW, is NOT el-cheapo RAM - they are a name brand right up there with Corsair & Mushkin) he had laying around, saw that the machine booted to BIOS or Command prompt, and called it good. YOU got the joy of finding out why PC2100 doesn't always run in place of PC2700....

mnem<~~~Happiness... we're full of it!!!~~~<<<

 

That's one thing that irks me about motherboard releases. People mention CPU types as well as southbridge specs, so you can get an FSB #, but you don't always get a northbrige spec, which, when present communicates with RAM. So basically, you can't rely on the FSB # to compute the maximum clock speed, minimum latency, and other parameters required for your RAM.

As long as the northbridge can interface with RAM at the same speed or faster than the FSB, then there's no problem. It's the faster bit that is causing the issue here.

 

Mnem.... That is the answer I was looking for. Thanks! Excellent explanation.

<Nobody knows what the dwagon knows!>

 

Not even HIM...

 

Is there anything the dwagon doesn't know or can't explain to us lesser being?

 

He is the MAN

 

The dwagon gives him the answers... I know that's what it is...

 

Well, not exactly... the issue here is that the Video Chipset is addressing the Shared RAM at speeds specified by the MB manufacturer, which in this case is optimized for PC2700 RAM, not PC2100. As long as it's operating at VGA or lower modes, the slower RAM can keep up. It's when the video switches to XGA or higher modes that it can't keep up, because the video chipset is expecting PC2700 RAM to be there, NOT PC2100.

The Northbridge can usually accommodate the slower RAM (Just like a desktop computer with an actual Video Card which has its own VRAM) for OS & application usage; but that blessed Video chipset is NOT as sophisticated, therefore not as forgiving when using SHARED RAM.

mnem
As for what the dwagon knows... I know just enough to have a clue how LITTLE I really know...

 

Isn't the Intel GPU for our toughbooks always located on the Northbridge?

 

It's all part of the same bus, it's true; but the usage of shared RAM has always been a bit of a kludged-together solution to produce a computer without the added cost of dedicated VRAM. You'd think Intel could come up with something that works after all these years... but then, you'd think they could have come up with a true 64-bit processor in less than the 10 YEARS it took them after Sun Microsystems had it on the market...

aTi has always been much better at implementing graphics solutions that ACTUALLY WORK; it will be a sad day when the Unholy Alliance between Intel & MS finally does kill off AMD, and aTi along with it.

mnem
Remember when MTV actually had MUSIC on it?

 

Yup... Those were the days... Sheesh... Those were the TRS80 days...

I guess I need to watch how I formulate titles and questions around here. It's becoming a little embarrasing to keep logging on here and seeing "DUMB" right above my name...

 

If it's any consolation Rick... I get a good snerk every time I see that...

mnem
Dumb is for amateurs.

 

Rick, remember, it is not what's above your name that counts, its what is below and you are da man! We all have our dumb moments, but dumb is one attribute we would not associate with Toughbook, the man or the machine!

 

Gee... Thanks guys...