Do hard drives consume significantly more power when they are accessed, or is power consumption fairly constant as long as the power is on? I want to make sure my PC case has sufficient cooling, and I’d like to know if I need to check the temperature during heavy disk activity.
I know some computers have power saving features that shut down the hard drive automatically, but I’m pretty sure my Linux box does not. (Maybe it has the capability but it’s not enabled.)
Yes, but overall, they don’t draw very much power. Typically about 4 to 10 watts active and less than 2 watts idle.
Power consumption (and heat) does become a problem if you cram a 4-drive RAID array into your case in addition to the original drive. So I can expect the drives to produce 2-5 times more heat when it’s being accessed? Thanks, I guess I’ll compile a kernel or something and see how hot the drives get.
I don’t believe disk access affects power usage significantly. I’d imagine that the motor that moves the heads accross the disk has minimal power usage compared to the motor that spins the platters at 7200rpm. As long as you aren’t working in a space restricted (rack mount) case, and you have adequate case ventillation in the first place, you shouldn’t have to worry about HDD temperatures.
He’s concerned about overall case temp, not just HDD temp. And with 5 drives operating at up to 20 watts active, that sure does represent significant heating. How much it really affects case temp depends on the duty cycle of his drives, that is, access time vs. idle time. An extra case fan couldn’t hurt.
Thanks for the help. Being an experimentalist I obtained a temperature sensor and stuck it on the hard drive surface. After a few minutes of heavy disk activity the drive temperature went from 31.5C to 32.5C and stabilized there. I expect the temperature variation in the rest of the case is smaller. The temperature probe doesn’t make good contact with the drive surface so the actual drive is probably warmer, but the spec sheet specifies an operating temperature of 0 to 60 C so I should be fine. I already have three case fans in addition to the power supply fan.
I’m concerned about the HDD temperature as well as the overall case temperature. I once had a hard drive failure which I blame on overheating. It was a Sun clone with a poorly designed case, and my office-mates used to turn off the air conditioning when nobody was in the office.
By the way, don’t connect/disconnect fans while the computer is on! It turns out that you can blow the voltage regulator on the motherboard. At least I think that’s what happened - all the fans stopped, and I had to get an adapter and connect all the fans to the power supply directly.
As an aside, a hard drive uses the most power when it spins up. If you have that many hard drives in your case, then I hope you have either a very big power supply or the ability to stagger their spin-ups at power-on.
-lv
Even though the drives and other PC components may spec up to 60 deg C operational temp, the reliability numbers start to turn south around 45 deg C. I tend to use 45 as an absolute max for everything in my systems.
Coincidentally, the human pain threshold for most people is between 40 and 45 deg C, so you don’t need any fancy temperature sensors. All you need to do is run it for a bit and see which parts are painfully hot to touch. This of course assumes that you have a little knowledge of electronics and know what is safe to touch and what isn’t inside a computer.
Since you do have a fancy temp sensor, try sticking it on the chips on your video card while you are running something graphically intensive. That tends to be one of the hotter components inside the case, and tends to be overlooked by a lot of people.
Thanks for the tips. I didn’t think about the spin-up power requirement - can IDE drives be staggered? I know most SCSI cards have that option, but I don’t think IDE cards do. I have a 335W power supply though so I’m not too worried.
I already know that the video chip is the hottest component in my PC. I decided to ignore it because a failed video card is unlikely to result in loss of data. Besides, the air temperature within the case is reasonably low.
I don’t know if/how/which IDE drives can be staggered. I’ve seen SCSI drives that actually have jumpers that set a spin-up delay. But that peak wattage the drive says it uses is the wattage it uses when it spins up, so you should be able to add those and get a good idea on their power requirement.
A simple way to help your video card is to not install a PCI card in the slot next to it.
-lv
I’m pretty sure IDE drives can’t be staggered, at least I’ve never seen any mention of it in the literature. FWIW, peak power consumption for the drives I’ve seen are specced out at between 1 and 3 watts over active power draw.