My next computer will be quiet #
I mentioned a few weeks ago that I wanted to buy a quiet computer. I did end up ordering a computer just like Nelson’s from endpcnoise.com. The store has good (but few) ratings at resellerratings.com. It’s taking a lot longer than I expected to get the computer though. I ordered it on January 12. It’s now January 31, and as far as I can tell, the computer hasn’t shipped yet (although they have charged my credit card already!). I’m glad I didn’t pay extra for faster shipping. It would have been silly to pay $150 to have the computer in 24 days instead of 26. The order status on their online page has been showing “Pending” since I ordered. I really miss the feedback that I get from Amazon—an estimate of when it will ship, whether it has shipped, and what the shipping tracking code is. That’s one of the reason I shop at Amazon but not at most other online stores: I know what to expect.
Time travel: is it possible? #
In some of the shows I see about time travel (and there aren’t that many), the claim is made that if you travel faster than light, you will go back in time.
I don’t see why this would happen.
If you read the laws of special relativity, you will find the formulas relating time and space. One of them (Lorentz contraction) tells you the rate at which you travel through time is sqrt(1 - (v/c)2), where v is the rate at which you travel through space. The quicker you go through space, the slower you go through time. But what happens when v > c? You get the square root of a negative number. You do not get a negative number; you get an imaginary number.
Alternatively, you can think of it as the Pythagorean theorem, where one leg of the triangle is speed through space, one leg is speed through time, and the hypotenuse is the speed of light. (Is this Minkowski space?) In this model, it makes no sense to go faster than light. You can’t have a triangle where one leg is longer than the hypotenuse.
So it’s not at all obvious to me how going faster than light makes you go backwards in time.
Another thing that bothers me is the talk of wormholes. Oh sure, if you could bend the entire universe in half, you might be able to go back in time. Bending the universe seems like a harder problem than time travel.
I do think backwards time travel could be possible. However, I think the only reasonable way to make it would be to travel from one universe to another. You have to believe in the many-worlds theory first. I don’t believe backwards time travel into the same universe can work.
Firefox customization: who's using "nofollow"? #
Google and a bunch of other folk are now using nofollow to mark links that are not endorsed by the author of the page. I just learned that Wikipedia is using this for their external links. (I’m not convinced this is a good thing, but given that Wikipedia can be edited by anyone, it’s reasonable.) How did I learn this? By using this Firefox/Mozilla custom style sheets.
Edit chrome/userChrome.css and add this:
a[rel="nofollow"]:before {
content: "[nofollow] ";
color: #393;
font-size: 8pt;
}
Now all nofollow links are marked with [nofollow]. To choose a nifty symbol instead of a word, pick a unicode symbol and use the hex code prefixed by \00 in the content: line. For example, to choose ☢, use content: "\002620";.
Economics of video cards #
In shopping for a new gaming computer, I wanted to do some research on video cards. The main vendors for consumer (gaming) cards are ATI and NVIDIA. What do these companies offer? Why do they offer these products?
ATI has the Radeon line; NVIDIA has the GeForce line.
ATI has several generations, named Radeon, Radeon 7xxx, Radeon 8xxx, Radeon 9xxx, Radeon Xxxx (example: X800). ATI is at the end of the line with “X”; they’ll have to do something else soon. NVIDIA has several generations, named GeForce 256, GeForce 2, GeForce 3, GeForce 4, GeForce 5xxx, GeForce 6xxx. Notice that they switched to something closer to ATI’s naming scheme. I wonder if their next generation will be the GeForce 7xxx, which will overlap with ATI’s numbers, so maybe they too will change naming schemes.
Within each generation they have several lines (low end, high end, etc.). ATI’s Radeon 9xxx comes in 9000, 9100, 9200, 9250, 9500, 9550, 9600, 9700, 9800. NVIDIA’s GeForce 5xxx comes in 5100, 5200, 5300, 5500, 5600, 5700, 5750, 5800, 5900, 5950 (I guess they ran out of numbers). The lines differ in functionality (vertex and pixel shader models, DirectX support, OpenGL support, antialiasing, shadow and lighting effects).
Within each of these they have variants. The Radeon 9600 comes as 9600, 9600 PRO, 9600 XT, and 9600 SE; the Radeon 9800 comes as 9600, 9800 PRO, 9800 XT. The GeForce 5600 comes as 5600, 5600 Ultra, 5600XT, and 5600SE; the GeForce 5700 comes as 5700, 5700 Ultra, 5700LE, and 5700VT; the GeForce 5900 comes as 5900, 5900 Ultra, 5900XT, and 5900ZT. Note that they aren’t really consistent in the variant names. NVIDIA doesn’t even use the same variants in each of their products. And whereas ATI’s 9600 XT is better than the 9600, NVIDIA’s 5900 XT is worse than the 5900. These variants differ in GPU speed, memory bandwidth, number of pipelines, and amount of memory. They also have “mobile” variants that consume less power and are therefore useful for laptops.
It also turns out that the same game will look different on different video cards. The rendering algorithms behave slightly differently due to differing spatial and temporal anti-aliasing techniques, anisotropic texture mapping, “shader” models, and support for various features in DirectX and OpenGL. (From what I read, NVIDIA is better at OpenGL and ATI is better at DirectX.) So you can’t only compare performance and price.
So there are lots of video cards to choose from, and each one of them available from multiple vendors (ASUS, Leadtek, ELSA, etc.). As far as I can tell, the vendors decide on things like fans, heat sinks, video in/out, DVI vs. VGA, etc. So you really have hundreds to choose from, and no really good way to evaluate them all. I can read Tom’s Hardware or ExtremeTech, but they tend to be a bit too much for me.
So in the end, I read about several product lines (GeForce 5700, GeForce 5900, Radeon 9800, Radeon X800) and a little bit about the variants and ended up choosing one. But I wasn’t happy about it.
Why do the video card manufacturers do this? I think confusion helps their profits. If I read reviews by searching for nvidia geforce 5900 review, and if I find products by using a comparison shopping engine, what will end up happening is that I will decide on a line based on reviews and then choose the cheapest variant in that line.
In practice this means that video card manufacturers should try to maximize the difference between the “plain” label and the cheapest variant. It should be better to make the plain GeForce 5900 a high end card so that it gets good reviews, but make available some very cheap variants. In fact, the GeForce 5900 comes in one higher variant (Ultra) and two lower variants (XT and ZT). The Radeon 9600 on the other hand comes in two higher variants (PRO and XT) and one lower variant (SE). So maybe my theory doesn’t hold up.
The difference between variants is so large that in many cases, the low end variant of a higher line is cheaper than a high end variant of a lower line. (Check out pricewatch.) When I last looked at this stuff a few years ago, the GeForce 4 MX was cheaper than the GeForce 3. I had thought I was getting a really good deal, and then I learned more about the “MX” variant—it was somewhat less powerful than the regular GeForce 4.
There will be some enthusiasts who pick the “best” card (whatever that means), but most of us will end up confused. Actually, most of us will use on-board video and don’t have to worry about this. I think that’s an important part of the economics here—the manufacturers want to confuse the people in the middle who are willing to spend more money but do not know what they are doing.
This is all a form of price discrimination. The video card manufacturers make lots of variants to increase the cost of evaluating the cards, so that only enthusiasts find the best deals. They make their profit from the rest of us. I’ve read that price discrimination can increase overall economic efficiency, but that doesn’t help me feel any better about all the time I spent trying to pick a video card.
Dyson vacuum cleaner #
Jeremy Zawodny’s post about his Dyson reminded me that I too want to say: I love my Dyson vacuum cleaner. I got the red DC07 model (base model + floor cleaner but no animal attachment), in part because I love the color red. (I know, that’s a silly reason.)
Consumer Reports says that it’s not as good as some other (less expensive) vacuum cleaners. However there’s an emotional attachment that many geeks have to the Dyson. I think it’s partly the Dyson story, partly the attachment system (which is annoying but cool), and partly the ease of maintenance. Or maybe it’s because the vacuumed dirt is visible so you can tell that it’s working. I can’t tell, really.
In any case, I like it.
Labels: review