ATX-P4 and a P3 system

HamaZ · Post by **HamaZ** » Fri Jun 17, 2005 8:14 am

Hi to every reader.

I own an Athlon T-Bird system from y2001. It was powered by some Foxconn 300W PSU since purchase, but the PSU died recently. Now I am looking for a new PSU, but I have come to doubts that these new ATX-P4 (or ATX12V or ATX2) PSUs are not so adequate for my system, which is an older "P3-type".

First, my system:

Standard:

CPU: Athlon Thunderbird B 1100MHz
MB: Asus A7V-E (VIA KT133)
RAM: 512MB SDRAM (1 module)
HDD: Maxtor 40GB 7200RPM (DM+

DVD: Toshiba 16x DVDROM
VGA: GeForce2 ULTRA 64MB DDR
SND: Hercules Fortissimo III 7.1
NIC: 3Com 3C-905B
FW: FireWire PCI card

Additional (occasionally added):

Full-sized three-channel PCI SCSI RAID HBA with cache memory
4x 9GB Seagate Barracuda SCSI HDDs, half height, "fat" server models
SCSI CDROM 32x
SCSI CDRW 32x

This additional equipent is the most probable reason why my PSU went off. These drives consume great amounts of power (about 20W each) and consider that they ALLWAYS pull power together because they work in RAID scheme.

Now, the main question:

Because my motherboard has no additional 4-pin 12V connector, it probably uses 5V rails to power the CPU. These newer systems use 12V rails for CPU. Because of that these newer ATX2 PSUs are more suited for such systems. Most of them have separate 12V output circuits. I suppose the first 12V is for the CPU only, and the second is for rest (HDDs, CDROMs etc).

That is the unbalance between my system's needs and ATX2 PSU's designs (at least I think it is).
I think that my system is mostly biased toward 5V usage, but it also considerably uses 12V when I attach these SCSI hard drives. And because ATX2 has one 12V rail dedicated to CPU only, and I am NOT going to use that rail, it means I am already wasting some potential of such PSU.

So what would be best suited for my system? I thought to buy a 400W PSU, but if I am going to waste one 12V rail than I get pretty much unbalanced power distribution which ends as bad purchase at the end.

Is there still a chance to find an "old" ATX PSU in markets?

Devonavar · Post by **Devonavar** » Fri Jun 17, 2005 9:36 am

You're not likely to find new PSUs that are biased towards the 5V line, but there are still a few ATX12V v1.3 PSUs available that have a more even split between the 12V and 5V lines. If I were you, I'd have my eyes on one of these. The 1.3 standard doesn't use the dual 12V rails either, so you don't need to worry about splitting the power. I suggest looking for a Seasonic Super Silencer or Super Tornado, if you can find them, or perhaps the older 1.0 version of the Enermax Noisetaker line.

HamaZ · Post by **HamaZ** » Fri Jun 17, 2005 1:19 pm

First, I need a straight confirmation of my statements I made in the original post.

I only THINK that my system is more biased toward 5V line but it also needs a lot on 12V because of SCSI disks. I also THINK that these ATX2 PSUs are not so adequate for my system, and that ATX1.3 would be the best for me.

Is ALL this correct and true?

Now, the problem is that my budget for PSU is limited. I can't possibly spend more than 40EUR (around 50$) MAX for a PSU. I also live in southeastern Europe, so the PSU pallete in local stores is much narrower than it is in USA. I have also noticed that many PSU maker companies use different names in different regions (very suspicious and confusing).

So, I would appreciate to tell me some five-six good ATX 1.3 PSUs in this price range, and possible alternate names of the companies which make them.

And the silence of PSU is not so much important for me. I want quality. Of course I also want silence but I am not a freak about it. So don't reccomend me the most silent ones, but the good ones for this (or less price).

HamaZ · Post by **HamaZ** » Fri Jun 17, 2005 1:25 pm

P.S:

And could somebody approximate how powerfull PSU is just enough for my system including the SCSI equipment? Consider that all those four SCSI drives work together at any time because they work in RAID scheme.

I thougt about 350W as lower limit or a 400W to be just fine.

?

sgrossklass · Post by **sgrossklass** » Fri Jun 17, 2005 1:55 pm

From the datasheet, those old Cudas need ~12 W in idle, ~.7 A on +12V and .8A on +5V. Your system needs quite a bit of juice on +5V (indeed, the VCore regulators work off this rail on your board) and then a moderate amount on +12V. IMHO you should be fine with a Fortron FSP300-60PN(PF) (or the 350 watter), the FSP400-60PFN would be almost overkill. A HEC300LR-PT is also regarded to be a very solid 300 watter.

alglove · Post by **alglove** » Fri Jun 17, 2005 2:12 pm

There are links to power calculation tools posted around this forum, but for now...

All your hard drives and CD-ROM drives probably have their +5V and +12V requirements written right on them. If you look at those and and them all up, that should tell you how much current they will require at full load, without guessing.

If I remember correctly, the power dissipation for a Thunderbird 1.4 GHz is about 70W. As you say, your motherboard uses the +5V rail to power the CPU, so guess you need about 14A on +5V for your CPU.

The RAM probably takes from +3.3V. The PCI cards probably take from +5V or +3.3V. The graphics card can take from +3.3V, +5V and +12V. For now, add up what you get for the hard drives, CD-ROM drive, and CPU. We can always find the rest later.

Actually, can you post some of the power supplies that you are looking at right now? That would probably be easier for me, since I do not live in southeast Europe. That way, we can say, "That one looks good," or "That one is not big enough."

Just for reference, here are the specs from the Enermax EG301:

total power: 300W
combined +3.3V and +5V: 170W
+3.3V: 28A
+5V: 30A
+12V: 22A
-5V: 1.0A
-12V: 1.0A
+5Vsb: 2.2A

HamaZ · Post by **HamaZ** » Sat Jun 18, 2005 8:57 am

First, I apologize for this long post, but please read it because it is important for me to make a good choice when money is tight. Thank you for your time!

When I said that PSU pallete in computer stores here is narrow, I meant it is VERY POOR (It's a poor country so this is not a surprise). To keep the story short, after checking the only four computer stores which are larger than a car garage, this is what they offer:

Bad PSUs and too expensive PSUs:

- no name PSUs for 10EUR are the most offered, and Codegen PSUs but that is the same crap as no name
- Enermax PSUs but they are over my budget. They have a 300W model EG301P-VE, but it is priced more than 45EUR. The 353W one costs more than 65EUR. I said I can afford MAX 40EUR for a PSU.
- Tagan and Antec but they are way too expensive.

The candidates:

- Chieftec PSUs; 350W model (GPS-350EB-101A) costs 30EUR and 410W model (ATX-410-212) costs 35EUR. The problem is that both are ATX2 models. They also offer 360W and 420W model (very different that previous two) for similiar price but all of them are ATX2.

I have also discovered that Chieftec's PSUs are infact prepacked FSP PSUs.

I have called one firm this morning and asked if, and for how much, they could get me FSP 350-60PN (PF). That is an ATX 1.3 PSU. Waiting for response which will take some days.

I have also another option. A friend of mine offers me the same Enermax 300W PSU as in the store, for 20EUR. His one is little more than a year old at it had relatively easy life (Athlon XP 2200 OCed to 2500, 40GB and 80GB HDD, DVDROM and DVDRW, 9200se, 512MB DDR, etc.) I borrowed it from him for testing. I write this text "from" it.
P.S.: In the original post I said that actually "I had" this PSU and that IT failed, but I made a mistake. I had some generic Foxconn 300W PSU.

His offer sounds like a good one, but I don't know is a 300W PSU enough for me? If my system needs, for example about 250W then 300W is not enough because I should keep the load at 2/3 of PSUs maximmum load, right? So in case of 250W usage the PSU should be rated at 350-400W. I mean, as I know, even a 300W PSU will work with 250W load, but it will be an overburden for it. That is at least how the book says.

Now I am not sure how much does my system need. Could you approximate that? Here are some ratings:

Maxtor 40GB: P = (12*0,79) + (5*0,65) = 13W
DVDROM: P = (12*0,65) + (5*0,65) = 11W
4x Barracuda: P = ((12*1) + (5*1,1)) * 4 = 4*17,5 = 70W
CDROM: P = (approx. as DVDROM - didn't check) = 10W
CDRW: P = (approx. as DVDROM - didn't check) = 10W

TOTAL: P= 110-115W

That is the rated power usage of the storage subsystem. This is the worst case when I attach all those devices.
I don't know how to obtain power needs of my motherboard, RAM, CPU and expansion cards. Can you approx. that based on my system specs?

My notices with Enermax:

Motherboard reports the 5V as 4,87-4,90V when "standard" configuration. When I add the SCSI system, the 5V drops to 4,80-4,83V.
12V and 3,3V are relatively fine (3,27-3,3 and 12V is 12,05-12,10).

In my friend's system, 5V is ussualy 5.00 and never drops below 4,95.

I can't believe that my machine is such a power eater, even without the SCSI.

HamaZ · Post by **HamaZ** » Sat Jun 18, 2005 9:01 am

So, in general: my options:

1.) Buy one of Chieftec's PSUs, for example a 400W for 35EUR, but it is ATX2, so it means a lot of money for mediocre solution.

2.) Search for a FSP 350-60PN (PF) PSU. That one is ATX 1,3. I don't know it's price yet so maybe it is out of the game already. I don't know.

3.) A second-hand Enermax 300W EG301P-VE from a friend for 20EUR.

4.) In case of selection 3., if that Enermax PSU is not powerfull enough, maybe I could combine it with one sh**y Codegen 300W PSU which I would include only when attaching the SCSI system and the Codegen PSU would be dedicated to the SCSI system only. It doesn't bother me to mess with two PSUs from time to time since I mess with the SCSI gear anyway.

In case 4. the only question is, is this Enermax PSU enough for my standard system? I provided the voltages, you tell me.

5.) Give me your option.

Post by **MikeC** » Sat Jun 18, 2005 9:13 am

Your friend's used Enermax should be fine. Just ensure good case airflow if you want to maximize its life.

alglove · Post by **alglove** » Sat Jun 18, 2005 9:55 am

Let us calculate the current loads a little bit differently. Let us take all the +12V values together:

Maxtor 40 GB: 0.79 A
3x DVD-ROM: (3 x 0.65 A) = 1.95 A
4x Barracuda: (4 x 1 A) = 4 A

This is a total of 6.74 A (81 W), not counting graphics card, case fans, etc. Since the Enermax can supply 22 A on +12V, you are looking good here.

Now let us look at +5V together:

Maxtor 40 GB: 0.65 A
3x DVD-ROM: (3 x 0.65 A) = 1.95 A
4x Barracuda: (4 x 1.1 A) = 4.4 A
Athlon 1.1 GHz: 14 A

This comes out to 21 A (105 W), not counting graphics card, PCI cards, etc. The Enermax can supply up to 30 A on +5V, and this still leaves about 65 W for the rest of your PCI cards, RAM, etc. on the +3.3V and +5V rails.

Looking at Chieftec's website ( http://www.chieftec.de/?page=products_c ... anguage=uk ), it looks like the GPS-350EB-101A and ATX-410-212 are NOT good choices, because they do not supply enough power on the +5V and (3.3V + 5V) rails.

However, the Chieftec HPC-360-202-DF looks like it would work. This would probably be my first choice. It supplies 35A on +5V and 220W on (3.3V + 5V). This looks like it should be plenty for your computer. As you see in this case, a 360W power supply can be better than a 410W if it gives you what you need.

My second choice would probably be your friend's Enermax. The case ventilation MikeC talks about is probably to make sure it remains cool, since power supplies usually become less efficient when they got hotter.

HamaZ · Post by **HamaZ** » Sat Jun 18, 2005 11:26 am

Thank you a lot for analisys and checktrough.
I could do separate power analisys myself but I waited for complete system's power usage estimation.

That Chieftec 360W look suitable indeed, and I did have that PSU in as my option before. The problem is that the only store which offers Chieftec PSUs doesn't have it available currently, and they won't receive new shipment of those for at least a month. And I want to solve this relatively quickly. The other minus is that it is ATX2 so it has two 12V lines of which I will be using only one.

Anyway, I am leaping toward the Enermax. I will probably pair it with some lame PSU when using SCSI, just for Enermax's sake. The only thing which still bugs me is that relatively low 5V level reported by motherboard's BIOS even when using standard configuration only. (4,87-4,9V). Is this relatively low?

I am planning to try to overclock my system a little bit, so I am not sure is such 5V level a good start.

One another problem is that I have to tell my friend am I a buyer or not BEFORE midnigt, that is about two hours from now!

Post by **MikeC** » Sat Jun 18, 2005 12:49 pm

Don't bother about a 2nd PSU -- it's much more trouble than it's worth. As for the 5V rail, +/- 5% is all it needs to be, measured at the output of the PSU. I am guessing you're getting your 4.87V off a motherboard utility or the BIOS, which is taken somewhere on the board, subject to further voltage drops through the board circuitry. A multimeter at an output connector of the PSU would be more accurate. Either way, it's well within 5%, not a thing to worry about.

HamaZ · Post by **HamaZ** » Sat Jun 18, 2005 1:11 pm

Thank you everybody for your help.
I have chosen Enermax PSU. Maybe I will pair it with another PSU for SCSI.

And for the 5V readings, I have taken them from BIOS (or better say CMOS setup). I have also checked them with good analog voltmeter but no human is capable to accurately read 0,01V differences on analog scale. Digital voltmeter is much more suitable but I need a quality one for accurate reading, which I don't have and nobody wants to borrow such a thing even if he has one (rare).

Off topic: How would you rate my english grammar knowledge (only grammar, not spelling)? Some people told me that they could never tell from my text that English is not my native language. I really don't believe that I am so good.

Devonavar · Post by **Devonavar** » Sat Jun 18, 2005 3:25 pm

HamaZ: I agree with Mike, I think the Enermax was an ideal choice for your system. Good choice!

I would rate your English as pretty good. I'm not going to say perfect, but I can think of very few native speakers that would earn that from me. I'd say your English is just as good as the average user on this forum.

alglove · Post by **alglove** » Sat Jun 18, 2005 5:58 pm

I think you made a good choice with the Enermax. I also think that your English is pretty good. To be honest, it surprised me when you wrote that you were in southeastern Europe.