Is a top Blowhole useful or needed?

[johnrr6]

Originally Posted by Rick_EE

Has anyone noticed a rise in temps when turning off their blowhole? No offense, but no one advocating the blowhole has shown any evidence that they are needed.

For me, it would matter more watching hard drive and other sub system temps, than for the cpu.

Good point....

OK----I Did....a couple of years ago....

I experimented with all kinds of fans, speeds, direction of flow, where the air was coming from (front/side) etc.

with a Lian Li aluminum case....

With Blowhole covered for one way----and with blowhole open with an 80mm fan running at low RPM----virtually silent....for the other

There was an average of 2-3C SYSTEM temp difference.
CPU temp did not change.

When running prime 95 (this was before dual cores)-----the difference was more remarkable 4-5 C System Temp
And the CPU WAS affected as it ran 2-3 degrees cooler with a blowhole compared to not.

So-----it DID make a difference on my very unscientific tests.

Not much----but I'll take 4-5 C cooler under stress ANY day of the week.....

John

[CrowdAds]

[fvbounty]

Originally Posted by johnrr6

Good point....

OK----I Did....a couple of years ago....

I experimented with all kinds of fans, speeds, direction of flow, where the air was coming from (front/side) etc.

with a Lian Li aluminum case....

With Blowhole covered for one way----and with blowhole open with an 80mm fan running at low RPM----virtually silent....for the other

There was an average of 2-3C SYSTEM temp difference.
CPU temp did not change.

When running prime 95 (this was before dual cores)-----the difference was more remarkable 4-5 C System Temp
And the CPU WAS affected as it ran 2-3 degrees cooler with a blowhole compared to not.

So-----it DID make a difference on my very unscientific tests.

Not much----but I'll take 4-5 C cooler under stress ANY day of the week.....

John

Nicely put, it seems like a no brainer that a blowhole would keep the whole system cooler just because of hot air rising and a place for it to escape, fan or no fan....thanks for your figures

[Rick_EE]

Sometimes what people think is common sense turns out not to be the case. Too much junk science happens this way. So often there is a factor that doesn't get thought of.

I agree that a blowhole should help. I would want proof. John provided some.

Common sense also would say that good side fans that turn over all the air in the case at a rapid enough rate would probably be just as good as a top hole. But I have no proof.

[Gorganzola]

I had my Pentium IV 550 3.4GHz Prescott w/1MB cache and a Radeon X700 Pro running in a full tower case, Antec SX1200, the heat that built in there kept causing video issues. I moved it to another case that I took the dremel too, and it did a bit better, but really it only delayed the video card over heating. With the Antec Nine Hundred, not only is the system running 20C less on the CPU, everything else is running cooler too. I really don't mind the sound of the fans. It's soft.

[fvbounty]

One other thing with having a blowhole(I have no proof, just a guess), your PS (if its on top like mine) wouldn't be doing all the work of getting rid of the hot air, and would probably prolong its life!

[Gorganzola]

I have to say, with the Antec 900 and the PSU on the bottom the PSU doesn't put out hot air at all. With the same PSU in the other case, it was pumping hot air like you wouldn't believe. For $110 it was a worthwhile purchase.

[fvbounty]

Originally Posted by Gorganzola

I have to say, with the Antec 900 and the PSU on the bottom the PSU doesn't put out hot air at all. With the same PSU in the other case, it was pumping hot air like you wouldn't believe. For $110 it was a worthwhile purchase.

I just checked my Corsair HX620 and my Blowhole 120mm fan the PS is slightly warmer than the blowhole I would guess a 3C difference, either one is warm to the touch, and my rig has been on since 6am this morning!

[ctal]

OK folks, here is some additional hard data, based on tests I ran today using the system described in my profile. The Coolermaster case is not particularly big (19.25" D, 17.75" H, 7.75" W). Cabling is generally well done and does not impede airflow significantly, but the case is heavily populated with 3 hdd's, 2 optical drives, a floppy drive, 3 PCI cards, the video card, and a very large Scythe Samurai Master Andy cooler for the cpu (with an Antec 120mm tri-speed fan in place of the slow stock fan, running on medium speed). There are four 80mm case fans (2 on the front, one on top, one in the rear). The stock top and rear fans I have replaced with Antec 75008 temperature sensitive variable speed fans (1650 to 2850 rpm). The two front fans are stock. The mobo is an Asus P4C800 Deluxe, and the cpu a P4 2.8C Northwood which I normally run overclocked to 3.24 GHz. That has proven to be stable over a several hour period running one instance of Prime95 (the cpu is hyperthreaded; I have not tried running 2 instances).

After running Prime 95 for 30 minutes in this configuration, Speed Fan indicated the following:

Mobo: 82 degF
CPU: 117 degF
HDD0: 88 degF
HDD1: 79 degF
HDD2: 84 degF
Rear Case Fan: 2394 rpm.
CPU Fan: 1722 rpm (fixed).
PS Fan: 1974 rpm.

After disconnecting the blowhole fan and putting a book on top of the blowhole grille, Prime95 would crash the system consistently within a few minutes (Windows would totally freeze).

I then turned off the overclocking (running the cpu at 2.8GHz). After 30 minutes of Prime 95, readings were as follows:

Mobo: 84 degF
CPU: 117 degF
HDD0: 90 degF
HDD1: 81 degF
HDD2: 86 degF
Rear Case Fan: 2520 rpm.
CPU Fan: 1722 rpm (fixed).
PS Fan: 1951 rpm.

So the bottom line is that with the blowhole & top fan, overclocking a cpu (which in this case is known to not be a particularly good overclocker) by 16%, readings were very similar to (and in some cases slightly better than) the readings in a non-overclocked condition without the blowhole & top fan (in which case comparable overclocking could not be achieved).

Regards,
-- Al