HTPC Double Case

[FuriousGeorge]

I started building a PC that I suppose msot people would characterize as an HTPC. One of the major problems I immedately notcies as a quazi-performance enthusiast, is the cooling, space, and power issues created by the desktop style cases and there weak, often micro-atx PSUs.

a solution I came up with was to put devices in a second case. if one wanted to (and i kinda do) one could put a second psu, a condensor and pump for water cooling, and all kinds of junk in there.

i got some questions about logistical issues with this.

for starters, the maximum length for IDE, as I inderstand it, is 36 inches. even worse, im having problems fidning cheap, modern, scsi dvd drives, and im beginng to think they dont exist. I know the cases will obviously need to be somewhat close if they are to have 2 PSU's, but 36 inches gives me very little to work with. the obvious solution would be USB, but this brings up a few other small concerns.

regarding the ide usb conversion, since i want to put them in a case, i dont want an external drive or enclosure, so do external enclosure makers have ide-in-usb-out converters that can be used w/o the rest of the enclosure?

in terms of bandwidth, usb 2.0 is 60 MB/sec, ide 133 is theoretically 133 MB/sec, but cd's read at 52 X which is 52 X 1,385,000 = about 70 MB/sec.

both are half duplex, so how can someone sell a 52X external usb drive? am i going to run into bandwidth problems when copying cds and dvds, eventhough read and write speeds are only around 16X, multiply that by two drives and we are up to 50 MB/sec, and there will ben other devices using the USB bus, no doubt.

are there other problems with using the USB drives that I'm not seeing? I already know my MB can boto off them, but, for instance, does throughput decrease a bunch on, say, a 6 foot cable?

for the hd, i can use SCSI, and since I always wanted a reason to get a SCSI drive anyway, the price doesnt so much bother me. But what about the line from the PSU? what cable length do i need to worry about for that?

any help would be much appreciated.

[FTC]

Hi, I think you have some numbers wrong. First of all, a 52x CD unit is NOT 52x1350KB, but more like 52x150KB, or about 7.8MB/sec. (1350 is a DVD 1x),

Now, regarding USB2, even if the bus clocks at 480Mbits/sec (60 MBytes/sec), you will hardly see any USB2 implementation that can effectively transfer more than 35MB/sec in real life. And even in that case, this is with a lot of processor support (no DMA mode equivalent).

All this said, you can easily see that USB2 bandwith is more than enough for a CDRW unit, and even for a DVDRW, BUT my suggestion is that you go the SATA way... less processor usage, bigger real bandwith (close to 150MB/sec, more than enough for even a RAID0 setup!)

[FuriousGeorge]

All this said, you can easily see that USB2 bandwith is more than enough for a CDRW unit, and even for a DVDRW, BUT my suggestion is that you go the SATA way... less processor usage, bigger real bandwith (close to 150MB/sec, more than enough for even a RAID0 setup!)

the only problem with that is again the cable length. 3.2 feet or ~38.5". the only way that is not so bad is if I run the drives off a PCI control card with external inputs. remember, i have to go from the drives in the middle of the other case, to the computer with the mobo.

what about using an ide to scsi converter? is there such an animal, and would it function more or less as any other cd/dvd drive.

update: what about this: Found on NewEgg (http://www.newegg.com/app/viewProductDesc.asp?description=15-114-104&depa=0). it looks like that mounts on the back of the drive, and it has an onboard risk chip to free up my cpu. (thanks for pointing that out btw, i overlooked that entirely)

update update: this may not support cd/dvd roms

[FTC]

Yep, you are right. Max SATA cable length is 1 meter... so and unless going the SCSI way, your only other option would be firewire, which allows for 4+ meter cables, does work in DMA-like mode (not much processor involvement in transfers), and allows for even faster than USB2 transfers in real life.. (close to 40-45 MB/sec). The only drawback would be finding CD/DVD drives with firewire interfaces... but I guess double interfaced enclosures can be easily found, so it may deserve some investigation....

[FuriousGeorge]

only problem with firewire is that i cant boot off it

[sangram]

I had similar issues and realise it starts with the case/PS itself, and the ability to keep requirements realistic.

My HTPC uses mostly recycled parts, except the case and PS that are both brand new. The case has been carefully selected so it has adequate ventilation, and comes with a 350 watt PS that is not maybe ultra high-end but adequate for powering an 1800+ Pally (itself a hot and power hungry monster), the MX200 card, a single hard drive and single optical drive. I have also run it succesfully with a GeForce 6800GT to test, it has no problems handling that either.

The only problem is heat, which the case addresses beautifully. It is almost a mirror copy of the Intel SFX reference design, but without the ducting, and with a fully ventilated top cover. The temps are completely within control, with a max load temp of 50-52 degrees C using a Volcano 5, not the best of heatsinks. An upgrade to the Volcano 12 will help a lot, maybe 6 -10 degrees or so.

Only HDD temps are a concern as the HDD and the floppy are sandwiched together. A single 40 mm fan blowing on the HDD should help a bit, this is my weekend project.

In your instance, what is the division of parts you are planning between the two cases?

I would keep the Hard disk and the CPU/Mobo near each other. The Small factor cases usually have a 5 1/4 bay. Use a mounting kit and mount the drive there with its own cooling fan. That will keep the drive cool and will ease the cramping. Look for the 250-300GB drives, should last you a while.

Take the optical out of the case and use a USB 2.0 connection. Should be enough for 4x DVD writing too.

As for performance, a SFX supply should be able to power 200 real watts, so a power hungry CPU (80/90 watts?) and a 6800GT (60/80 watts?) together should not be a problem. The only real dilemna is cooling, and how to keep the beast silent. It starts with case selection. Ventilation, fan layout and placement/air flow are important considerations.

More than anything in these cramped cases getting fresh air into the case is more problematic than getting the hot air out. My case has a fully punched-in side cover which I have covered with a layer of filter cloth. I remember the earlier version of the case had a solid side cover, so obviously there have been heat problems in the case which are now addressed. Ducts and chimneys are also a good method to keep the stuff inside cool. PCI slot blowers modded to 7 volts will serve as good secondary exhausts...

Mostly you can serve all your requirments with one case and few compromises. What are your requirements? we could brainstorm a bit.

[FuriousGeorge]

thanks for the great reply

i love my case, its the ahanix d4. the second case idea is not so much a "lesser of two evils" situation, as it is just an idea thats interesting to me. i think it would be cool and pragmatic to someone who wants to leave the door open to a second PSU and watercooling, even with a small desktop case.

that said, it is a solid cube w/ two exhaust fans in the back. there is no ventilation. not on the top, bottom, or sides. the only opening (besides on the back of the case) is a one inch gap that runs along the bottom of the case where it meets the face of the case.

with the two exhaust fans and by placing fans in the right places, i'm able to create enough negative pressure to draw air pretty effectively from under the face of his case. my average case temp varies from between 27 C on a good day to 33 C on a bad one, my idle cpu temp is usually b/w 39 C and 43 C, and my load temps go between 47 C and 51 C.
I cant account for the variation, though i think it has something to do with the door to my room being open.

so my temps arent so bad, and unlike my last HTPC case, the PSU can be changed, and isnt as bad (my system doesnt begin to randomly shut off until the VCore is raised to about 1.9). so i think getting a second case will increase my options, not limit them.

its not like I'm making a laptop, its not going to be portable anyway, and a component stereo system would take up more space and do less. so the point is, if i can get the same functionality, i think its worth it.

functionality is the important thing. if i kept the HD in the same case, i could use my master case independantly of my slave case. i'm finding that a company called adonics makes an internal ide/atapi - scsi converter you can mount on the back of drives, and convert them right to scsi.

the fact that it free's op CPU usage makes it a better solution than usb, and the max cable length is much better than sata or ide. the only advantage i can think of for USB is that a USB slave case would be hot-swappable. who knows, maybe with the right scsi controller card, i could achieve the same thing