Dan's Data letters #12
Publication date: 20-Nov-2002.Last modified 03-Dec-2011.
Phantom improvements
I recently bought a new motherboard (having replaced my old 500MHz Pentium) and box, and moved my drives from the old box into the new. I used the same old 40 conductor IDE cables to connect the drives. But I noticed during boot that the new BIOS was whining about the lack of the 80 conductor IDE cable. It all still worked though.
OK, I says, I'll pop for the $5 (US) and buy the 80 wire cable, just to make the BIOS happy.
I installed it, the message went away, and everything is hunky-dory. I am wondering though, am I fooling myself when I suspect that transfers are faster? I looked at some sites on the Web talking about this new standard, and while it's still not great the signalling should be more reliable, which may mean faster transfer rates, no?
Mike
Answer:
You're probably fooling yourself.
If you've got two ATA hard drives on a single IDE channel, and they're both transferring data as fast as they can, then they can be quite seriously held up by Ultra DMA/33, which is the fastest transfer mode you can use with a 40 wire cable. The very fastest ATA drives today can manage about 50 and 30 megabytes per second for read and write operations, respectively. The ceiling bandwidth of UDMA/33 is 33 megabytes per second, and its actual real-world bandwidth is somewhat lower.
Ultra DMA/66, 100 and 133 have the ceiling bandwidths you'd expect from their names, and the extra transfer rate capacity does indeed make a difference, for disk-intensive tasks, provided the drives are fast enough.
Most of the world's ATA drives aren't nearly as fast as the fastest ones you can buy, though, and if there's only one drive on a channel (or only one drive doing anything on a channel at a time) then that halves the load.
The clincher, though, is that drive performance doesn't have much impact on system performance, for most tasks. Sure, if you're pushing vast database data sets around or doing video editing or something then your drive speed can be a real limiting factor, but most Windows boxes that flog their drives do so because they don't have enough physical RAM. The cure for that is more RAM, not faster hard drives; making the swap file faster just somewhat reduces the amount by which an under-memoried computer will suck.
Even with one drive that's nowhere near saturating the ATA interface for sustained transfers, there'll be a measurable performance gain from moving up to UDMA/66 or better, assuming the drive supports it. That's because the full interface bandwidth can be used for reads and writes from and to the drive's buffer memory, no matter how slow the drive itself is. The buffer memory is only likely to be a couple of megabytes in size, though (eight megabytes, at most), so the effect the faster buffer has on real world tasks involving the transfer of a lot more data than the buffer can hold is minimal.
Sony software
Could you tell me where to download the software that would have come with a Sony MVC-CD1000 camera? I have one that I bought used with no manuals or anything else for that matter, and it takes great pictures, but I can't get them off the camera or the CD. I suspect I don't have the original software and that may be the problem.
Larry
Answer:
Hm. No manuals, no cables, no software... I don't suppose you bought the
camera from a bloke in a pub?
I don't know where you can get the whole MVC-CD1000 software suite (Sony's various sites are heavy on the graphic design and light on the actual HERE ARE DRIVERS FOR OUR BLOOMING PRODUCTS links), but you can get Win2000 and WinME drivers here. You can find a manual here.
No special software should be needed to read the CD1000's discs, by the way. If you finalise the CD in the camera, you should be able to read it in any CD-ROM drive that's compatible with 77mm CDs, and understands CD-Rs.
Cooling contact
In your two recent additions to the cooler comparison, you said the Vantec VA4-C7040 scored 0.58°C/W, while the VP4-C7040 managed 0.49°C/W. Aren't these the same heatsink and fan, with just very slight modifications to allow them to fit on different sockets? If so, how did they get such different scores?
Leigh
Answer:
Different contact patches.
The P4 contact patch - the raised area in the middle of the CPU that actually touches the heat sink - is much bigger than the patch for a Socket A CPU, and I use different patch simulators on my test rig to reflect that. You'll see the same effect with the "dual mode" coolers in the comparison, which can be used on both socket types.
Note that the recent "Tualatin" Socket 370 CPUs also have a large contact patch, as do the old pre-Coppermine Celerons; they're more effectively cooled by a given cooler than an Athlon or Duron or small-contact-patch Socket 370 chip would be. All of the big-patch Socket 370 chips are low enough power, though, that cooler choice isn't very critical anyway.
Power numbers
Do you know anything about Opti-UPS? Some of their UPS products are available at Aus PC Market. I was wondering why out of all the UPS products I have looked at, only the Opti ones can put out equivalent VA to W.
Take, for instance, the ES range; the 420ES outputs 420VA and 420W, and has a very good price (considering its other features) compared to other 420W UPS products.
The thing that caught my eye was that this 420 VA UPS doesn't succumb to the "multiply by 0.6" rule. How can this be? Have you an opinion on the Opti UPS range?
Archon
Answer:
My opinion about Opti UPSes is that they're perfectly fine. I'm using an
Opti 1000ES right now. It works. It was cheap. What's not to like?
Opti are playing a bit fast and loose with their VA (volt-amp) and wattage figures, though. Note that they're quoting "Maximum Capacity". The maximum wattage capacity of any honestly specified UPS will be the same as its VA rating; an honestly described 1000VA UPS (and I think the 1000ES is honestly described) will be able to run a 1000 watt heater, for instance, for the brief period before its batteries go flat.
A heater, toaster or incandescent lamp is a simple resistive load, and for simple resistive loads VA equals watts. The "power factor" of the load, in other words, is equal to one.
Where watts and volt-amps part company is when you start powering reactive loads, which includes PCs and lots of other things with motors and/or fancy power supplies in them. PCs typically have a pretty awful power factor; a 1000VA UPS like the 1000ES can reasonably be expected to only be able to power only about 700 watts worth of PC gear. Maybe less. There's the 0.6X multiplier you mention; that's a good conservative estimate to use when you intend to use a UPS with a PC.
But wattage figures are just guesses; different reactive loads have different power factors.
Note that the above does not mean that a 1000VA UPS will be overloaded if you plug in a PC with a 400 watt PSU and another PC with a 300 watt one. Unless those PSUs are actually fully loaded, they won't be delivering their full rated power to the PCs they're in. They'll draw more power than they deliver (because nothing is perfectly efficient), but even stacked PCs aren't likely to have a constant draw above 200 watts, not counting the monitor. Quite a lot of PCs come in at less than 100 watts continuous draw.
I talk about this a bit more here, and there's more about power conditioning in general here.
Smoking a PC
My dual processor PC just went tits up. The fella that takes care of my computers said that my smoking killed it. I've spent the morning looking on the Web for cases that can be used in hazardous environments, but have only found tons of places that sell entire kiosk type systems for things like factory control, and sites for military laptops. Then I ran across a piece on your site about ducted fans, which aren't what I want, but it got me thinking... (danger music)
A while back I read an article on homegrown liquid coolers for computers, which involved heat transfer to water circulated by thermal induction in a sealed copper tubing system. Having been trapped in HVAC (Heating, Ventilation, Air Conditioning) from the age of 13-21 (long story), I thought to myself "well, that's stupid, why not use a refrigerant, or ammonia, they used to use ammonia before they had Freon". Anyways, I decided to make a better cooling system, but I let it fall to the wayside when I couldn't readily find answers about using ammonia.
Now, I'm trying to find a way to make a sealed case for my computer, as I have no definite plans to stop smoking while I work, or stop working to break for a smoke. I'd like to hear anything you can proffer in the felid of recirculating air in a sealed case, or liquid cooling for the case environment. I don't think air filtration will be an option, but I'm ready to listen
Zoli
Answer:
It's possible that your smoking was what killed your computer. It usually
only happens to machines that've been used by chainsmokers for quite a while,
though; they typically look stunningly revolting on the outside before
they actually die.
The computers, that is, not the chainsmokers.
Well, OK, often the chainsmokers as well.
Smoke generally can't get into hard drives; they have no through-flow ventilation, and their pressure-equalisation holes are protected by very fine filters. But it can build up on other components, and carbon and other particulates in smoke precipitate can be conductive enough to cause problems in PCs and CRT monitors. Plain old household dust can do the same thing, but it's not as bad, and it's much easier to remove than smoke scum.
There are lots of water cooling options. I haven't reviewed any of them very recently, but you'll find my most recent reviews here.
The problem with using this gear to make a sealed computer case is that most of it's meant to cool only the CPU, and maybe the motherboard chipset as well, and possibly the video card if you're a real nut. Which is fine, but you still need some airflow to keep other components cool - drives, the PSU, some other expansion cards. You can get water cooling blocks and jackets for anything if you shop around, and they're not too hard to make, but they're not everyday items.
Personally, I'd try a less extreme solution. Don't park your ashtray in front of the PC's air intake, put a more serious filter in front of the intake, and use an air purifier in the room as well (filter-type, or maybe a phalanx of cheap ionisers), and you'll greatly reduce the problem. Alternatively, you could run a bit of air-con duct to the window so the computer sucks in truly fresh air.
Ionisers, generally, aren't up to much. You can tell they're doing something because they steadily make themselves filthy with electrostatically attracted dust; their method of operation is to create lots of negative ions in the air around them, which cause particulates in the air to become negatively charged and stick to relatively-positive surfaces around and on the ioniser. Better models of ioniser have separate dust-attractor plates that are easy to clean. But domestic ionisers generally don't actually do enough to have a real impact on air quality in a room. Some people think negative ions have beneficial health effects, but they sure don't do much for dust and smoke.
There are big ionisers that do really clean up the air, but they cost a fortune and building one yourself is a serious high voltage project.
Air filters are a more sensible proposition. Filters that can deal with pretty serious air contamination in a normal room are not hard to source, or hideously expensive. You don't need to get rid of every single smoke particle, after all; just greatly reducing the amount of smoke in the room would do the job.
(Yes, this does mean that just leaving a window open would probably go a long way towards solving the problem.)
There's also the old build-your-PC-inside-a-fridge trick, but that doesn't actually work terribly well, as refrigerator compressors that have to run all the time because there's an actual heat source inside them tend to die. Without the compressor running, the well-insulated fridge becomes an effective computer-cooker.
Help! Help! I'm being repressed!
I was just reading the information on your website and come across this next to one of your Aus PC Market links:
(if you're NOT from Australia or New Zealand, don't bother!)
Can you tell me why i or anyone else outside of the two stated countries should not BOTHER??
Is this discrimination in any form or kind?
Or is there a good reason why forien web surfers should not visit the site Aus PC Market. that you recommend?
If perhaps you DO have a very good reason, then we suggest you state that reason or change your wording.
I look forward to a reply.
Many thanks [name redacted].
W.W.W.L.P association
World Web-Watch Legal Practises Association.
London, England.
Answer:
People outside Australia and NZ shouldn't bother with Aus PC Market because
they don't ship outside Australia and NZ. It's too expensive; there's no
point. There are lots of mail order companies that don't ship outside their
country, generally for this same reason.
Foreign Web users are welcome to visit the Aus PC site all they like. They just can't buy anything there.
And yes, this is discrimination. There's tons of discrimination in the world. Discrimination is what keeps inmates in jail.
The word "discrimination" is commonly used as shorthand for "unfair discrimination". Which is fine, as long as you don't go the other way and decide that this means there's no such thing as fair discrimination.
Thank you for reading another DanRantŪ.
