Changing voltages.

[Spork Schivago]

Re: Changing voltages.

I count 4 coils next to the CPU, 4 caps total. Wouldn't that make it 4 phase?

Markings on the caps? They're a bit weird and can almost be read either way. I believe one of them says E89H. That's not from one next to the CPU though. Only way I can make them out is to pull the board. Something I didn't really want to do right now.

[Spork Schivago]

Re: Changing voltages.

I believe the way it works is the VRM converts either 5V or 12V to whatever the CPU uses. Correct me if I'm wrong there. I thought the VRM was part of the VRC (Voltage Regulator Circuit).

[ratdude747]

Re: Changing voltages.

The PSU is made by a company I've never heard of, Okia. It's 450 watt.

I tore a dead one (Okia 450W) open awhile back. JUNK!

[stj]

Re: Changing voltages.

I believe the way it works is the VRM converts either 5V or 12V to whatever the CPU uses. Correct me if I'm wrong there. I thought the VRM was part of the VRC (Voltage Regulator Circuit).

correct.
and with unstable incoming power, the caps on that circuit probably got even more stressed.

[dmill89]

Re: Changing voltages.

I tore a dead one (Okia 450W) open awhile back. JUNK!

X2, an Okia "420w" (yah right) I opened up awhile back is the biggest pile of garbage I've ever seen, they are even poor on "free with case" PSU standards:

[fzabkar]

Re: Changing voltages.

Just as an example, the 3.30V would be 3.344V or 3.60V. Never 3.350V, etc.

3.350V will never be reported by BIOS because 3350 is not an integer multiple of 16. The voltage can only vary in 16mV increments. That's the resolution of the A/D converter within the Super IO chip.

[keeney123]

Re: Changing voltages.

The board says the bus is 1600 MHz. Whether it's running at 1600 MHz or not, I'm not sure. The RAM is DDR-1066 with a CL5-5-5-15 (2.0 - 2.1v), G.Skill F2-8500CL5D-4GBPK. The base frequency of the FSB would be 400MHz, right? The BIOS only has options to run the RAM at 667MHz or 800MHz, but my understanding is, unless someone's overclocking the FSB, there's no real point in running the RAM at a faster speed. Probably why the board only gives the option for 667MHz or 800MHz. Am I right in thinking that?

I am wondering if that ram is compatible with that bus speed? Do you have the specifications on the computer? If it says the bus is 1600 Mhz I would suspect that is the speed of the Ram Bus. I have not study this for a while, but I am thinking that 1066 Hz Ram is not compatible with with a 1600 MHz bus. It works the other way around. That would be a higher frequency Ram is backward compatible, but because the Bus speed is faster the Ram of yesterday was not invented so would not be compatible. You are saying the forward bus is 400MHz this is an extremely slow bus. My Dell computer I had over 10 years ago had such a forward bus speed. To me I think you need to look up the Specs. on this computer.

[ChaosLegionnaire]

Re: Changing voltages.

errr there is no need to go through all that just to get the bus speed. just get the bus speed for the cpu. the pentium e5200 or pentium dual-core e5200 is an 800mhz fsb cpu. so the fastest u can run the ram is ddr2-800 using the 1:2 fsb to ram ratio. u cannot run the ram at 1066 using an 800fsb cpu cuz the nbmch lacks the proper memory divider ratio to run the ram at that speed. u need a 1066 or 1333 fsb cpu to run the ram at ddr2-1066. not sure where u got that 1600 mhz figure from, spork. either its a golden cpu chip that can do an amazing 100% overclock or u must have seen something wrongly...

[Spork Schivago]

Re: Changing voltages.

correct.
and with unstable incoming power, the caps on that circuit probably got even more stressed.

Okay, just wanted to make sure I fully understood everything. That's what I was thinking too. The unstable incoming power stressed some of the caps and they started failing prematurely.

[Spork Schivago]

Re: Changing voltages.

X2, an Okia "420w" (yah right) I opened up awhile back is the biggest pile of garbage I've ever seen, they are even poor on "free with case" PSU standards:

This one that I have is a 450 watt and I believe it was free with case! The guy bought one of those pre-built systems off e-bay for maybe 300$ a few years back I believe. It came with the board, hard drive, CPU, RAM, etc.

[Spork Schivago]

Re: Changing voltages.

errr there is no need to go through all that just to get the bus speed. just get the bus speed for the cpu. the pentium e5200 or pentium dual-core e5200 is an 800mhz fsb cpu. so the fastest u can run the ram is ddr2-800 using the 1:2 fsb to ram ratio. u cannot run the ram at 1066 using an 800fsb cpu cuz the nbmch lacks the proper memory divider ratio to run the ram at that speed. u need a 1066 or 1333 fsb cpu to run the ram at ddr2-1066. not sure where u got that 1600 mhz figure from, spork. either its a golden cpu chip that can do an amazing 100% overclock or u must have seen something wrongly...

The 1600MHz is printed on the motherboard. It says:
FSB1600
DDR2 800
Dual Channel

I misunderstood the original question and thought someone was asking what was the fastest bus speed the board supported, which is a 1600MHz bus speed. The CPU, E5200, runs with an 800MHz bus speed. I know the RAM won't reach those speeds, it drops down the speed. Maybe because of this, I could tighten the timings a little bit? It's supposed to be 5-5-5-whatever at 1066MHz. I wonder if at DDR2-800, I can get 4-4-4-whatever. The RAM is running at 800MHz (400MHz base), which is correct, as far as I'm concerned.

[keeney123]

Re: Changing voltages.

Yes Spork I believe you are correct as my knowledge is old. So the modern boards are divisible by the clock speed. So if you have two cores and they are running at 400 Mhz you then have 2X 400 MHz which is 800 MHz

[Spork Schivago]

Re: Changing voltages.

I'm a bit confused by what ChaosLegionnaire said though. The RAM is running at 800MHz but it has a base frequency of 400MHz. The CPU's FSB is running at 800MHz...but because it's a dual core, would the based frequency be 400MHz? Wouldn't that give a 1:1 FSB to RAM ratio?

[Per Hansson]

Re: Changing voltages.

I'll be sure to keep a lookout for this in future and I'll be sure to test the voltages with a DMM next time I work on a PC.

Thanks!

Thing is a DMM can't show ripple.
You could have a "stable" 12v readout but with 2v ripple peak to peak and the DMM would not show it.
(It might be able to show some of the ripple on the AC setting but it's a pretty useless test because you don't know how much of the ripple the meter is able to show if it's some cheap POS...)

Btw, the pictures of that PSU is what you should have started with.
It's not so much a PSU but more like a fucking disaster, it's amazing the computer has not been more problematic as it is with that POS.
When you connect the new one up you might come to see that everything works well again...

[diif]

Re: Changing voltages.

The number of cores in a processor has no relationship to bus speed.

[Spork Schivago]

Re: Changing voltages.

Thing is a DMM can't show ripple.
You could have a "stable" 12v readout but with 2v ripple peak to peak and the DMM would not show it.
(It might be able to show some of the ripple on the AC setting but it's a pretty useless test because you don't know how much of the ripple the meter is able to show if it's some cheap POS...)

Any good way to show ripple? I have a 200MHz (I think) oscilloscope. I also have a 1000MHz oscilloscope module for my logic analyzer. I just have to find the time to try and fix it. I've heard of ripple current but not exactly sure what it is. I've searched for the meaning before. I see, from Google,

The most common meaning of ripple in electrical science is the small unwanted residual periodic variation of the direct current (DC) output of a power supply which has been derived from an alternating current (AC) source. This ripple is due to incomplete suppression of the alternating waveform within the power supply.

What does that mean though? residual periodic variation of the direct current output...does that mean the output voltage varies on a cap?
When it says derived from an AC source...does that just mean the AC source isn't completely filtered out? I thought caps allowed AC through and blocked DC. They'd charge up and when the circuit path was "broke", they'd discharge, supplying DC voltage.

Btw, the pictures of that PSU is what you should have started with.
It's not so much a PSU but more like a fucking disaster, it's amazing the computer has not been more problematic as it is with that POS.

Okay. I just never realized that a power supply could be "flaky". I figured they either worked or didn't. I guess I just never thought about it. I wonder how many times I had a flaky power supply and because the PSU tester showed the voltages as good, I just assumed that wasn't the problem.

...
When you connect the new one up you might come to see that everything works well again...

That's what I'm hoping. If not, I'll start with the caps around the CPU and see what the ESR / capacitance for them are.

[Spork Schivago]

Re: Changing voltages.

The number of cores in a processor has no relationship to bus speed.

Okay, so with DDR2 type RAM, I divide the effective data rate by 2 to get the base frequency.

How am I supposed to get the base frequency of the FSB? If I multiply the base frequency of the FSB by the multiplier, I get the CPU speed. But how do I calculate that FSB base frequency?

[Per Hansson]

Re: Changing voltages.

Well if you have a scope I'm not sure why we are having this discussion with all of the rest of the FUD about RAM clockspeed related to how many CPU cores which is just completely bananas.

The ATX spec states that for the 12v line you may have a maximum of 120mV ripple.
And it's 50mV for 5v and 3.3v (easy to remember since it's a division of the major voltage )

So start up the comp again on the shit PSU if you are not afraid to kill it, connect the GND to any negative and the probe to 12v.
Set the scope for maybe 1ms and half a volt per division and coupling to AC, if the screen isn't already filled with shit then zoom in and see how much you've got

[stj]

Re: Changing voltages.

ripple current is the current (at the rated frequency) that a capacitor can absorb / release.

[Spork Schivago]

Re: Changing voltages.

Well if you have a scope I'm not sure why we are having this discussion with all of the rest of the FUD about RAM clockspeed related to how many CPU cores which is just completely bananas.

The ATX spec states that for the 12v line you may have a maximum of 120mV ripple.
And it's 50mV for 5v and 3.3v (easy to remember since it's a division of the major voltage )

So start up the comp again on the shit PSU if you are not afraid to kill it, connect the GND to any negative and the probe to 12v.
Set the scope for maybe 1ms and half a volt per division and coupling to AC, if the screen isn't already filled with shit then zoom in and see how much you've got

Okay. I never really had the time to learn how to use the scope so I don't really use it often. When I started making some simple circuit boards, I busted it out and saw how some of the components talked to each other, which was kind of cool.

For the RAM clock speed and the FSB base frequency, I'm just trying to understand it. I guess we kind of gotten off track with the original topic though.


For the scope part, that will show me the ripple?