Computer & Network Questions

[LarryG]

I have some general, almost hypothetical questions about Windows computers and networks.

Ground rules are that all computers are running either Win2000 Pro or XP Pro; and the network is small (about a dozen machines) and hardwired using Cat5 cabling and a 10/100 switch.

1. If certain machines on the network are much faster than others (i.e., CPU speed), can they "hog" the available bandwidth and cause other nodes to drop off the network?

2. Does using the Quick Launch toolbar (i.e., those small, single-click icons immediately to the right of the START button) cause problems or severely hinder the performance of the computer ... to the point that is highly advisable to turn this toolbar off and not use it at all? Note that I am not talking about the icons in the System Tray at far right, next to the clock; I know about those.

3. This one I barely know enough to ask the question ... with the newest motherboards, isn't DDR2 memory supposed to be installed in pairs of matching sticks, instead of a single stick, for the best performance? That is, if you want 512Mb of memory, will two 256Mb sticks perform better than a single 512Mb stick?

Thanks very much to anyone who can help.

[cgallery]

(1) No. Fast machines WON'T hog the bandwidth.
(2) No. Quick Launch has no real impact on overall performance.
(3) All motherboards I know of that use DDR2 are dual-channel capable. Which means you get a performance boost when using two matching (specifications) modules at a time. I spose there may be system boards out there that use DDR2 that aren't dual-channel, I just don't know of any. There are many occasions when I see dual-channel MOBO machines that come with a single stick of RAM. Especially on notebooks. And Dell.

If you want to get less hypothetical, just reply with more specifics. You kinda sound you're having a disagreement with someone about a computer that isn't functioning properly. Am I right?

Thanks!
Phil

[jziegler]

Larry,

I can't answer all of your questions, but I can help on some of them.

I don't think that hogging the network should happen, especially with a switch. It would be much more likely with an older hub. With the switch, each computer has a dedicated path to the switch, which can then route to the other computers. With a hub, the same thing goes to all of the computers on the hub. With the switch, only packets that are going to a computer end up there, which includes broadcast packets that go to the whole network. So, in general, a switched network doesn't suffer from having machines of different speeds.

I can't help on the quick launch question. I always just turn it off since I don't care for it.

As for the memory in pairs, it really does depend on the motherboard. Certain DDR motherboards are best in pairs. Basically, it depends on if the motherboard has a single or dual channel controller. A single channel controller can only access one stick of ram at a time. All sticks are in the same bank. In a dual channel controller, the memory is in two banks, and the controller can access one stick in each bank at the same time. So, if you have a dual channel board, installing pairs is best. Now, I don't know if they always have to be matched. I would imagine that even putting a small module in the second bank would give better performance than having nothing at all in it, but that may depend on the memory controller and many other factors. I have never tested anything like that.

Edit:

Unmatched apperas to depend on the memory controller used. In some controllers, you only get dual channel support with matched modules. In others, you can get dual channel support with unmatched modules. But, to be sure that you're in dual channel mode, use matched modules if you can.

As a note on this, I currently work designing a PCI express add in card that has DDR memory on it, so I am familiar with the way the memory works, although I don't know much about the implementations on current motherboards.

Jim

[LarryG]

You kinda sound you're having a disagreement with someone about a computer that isn't functioning properly. Am I right?

You're close ... very close. I'm the nearest thing our firm has to an in-house guru. An outside, er, "consultant" has recently entered the picture, and while there does appear to be stuff he knows that I don't, he apparently assumes I don't know enough to know when I'm being BSed.

[greencat]

When you said switch did you mean router? For the same cost I think you will get better performance with a router.

[wreckwriter]

All answers are basically no, but the memory one is trickier. As others said, you will get better performance with matched memory pairs. Will it be enough better to notice? I doubt it. Some mobos might require a pair, most won't.

Greencat is right though, a router is better than a switch.

[scorrpio]

1. Faster machines will not hog the network by themselves. However, if you have one fast PC pumping several gigabytes-large file to another, it might congest the network. Also, you might wanna check the network connection speeds (go to control panel, open 'network connections', and double click the connection to see its status). One of my home PCs is an older Pentium III machine, and copying large files to and from it always seems rather slow. Network speed check revealed it running at 10MB/s, even though it has a 10/100 card and cabling is Cat5. I even replaced the network card in it, but it still runs only at 10. So, it might be not faster machines hogging the network, but rather slower machines not taking advantage.

2. Quick launch icons bog the system down no more than icons on your desktop. In fact, I believe they use even less resources. I mean, EVERYTHING displayed on your desktop comes with a resource price, but for quick launch, it is negligible. BTW, the system tray icons don't use much either - it is the programs represented by those icons that use resources. I once knew this naive guy who thought that configuring toolbar to hide those icons would result in better performance.

3. As others explained already, many motherboards these days support dual-channel memory. To take advantage of it, two identical modules need to be installed in matching channel slots. For example, ASUS A8N5X mobo has four RAM slots, arranged into 2 pairs. In each pair, one slot is blue, and another is black. Each pair represents a channel. For best performance, it is recommended you install identical modules in same color slots.

[LarryG]

Thanks (so far), and another Q.

Thanks, everyone, you're essentially confirming exactly what I thought.

I should clarify that we're not having any network problems (or no apparent ones, anyway ... but with Windows, it's always something, isn't it?). This fellow has just built two new machines for us that he claims are so fast they will cause our network to "start dropping nodes." Not just congest the network, but actually force other machines to lose their connection. I've never heard of such a thing, and suspect it may be a ploy to sell us more new machines.

Another question:

4. Most of our existing machines are about four years old; all motherboards are identical (I built the boxes myself), with a mix of Athlon and Duron processors. My understanding -- correct me if I'm wrong -- is that the Athlon and Duron are essentially identical, the main difference being the amount of L2 cache, and that anything that will run on an Athlon will also run on a Duron, only slower. This outside consultant has told me that we need to replace our Durons because "in a couple of years it won't be able to run the newest software" but that "the Athlons are fine, no problem." Note that he's not claiming this future software will run more slowly on the Duron boxes but that it will not run at all, because of the L2 cache spec of the Duron. Crap, right?

[JR]

Larry,

A fast computer can only affect network performance by doing more things on the network faster, thereby consuming network resources (switch speed or server functions) dispraportionately. By and large a computer does so little with information coming from outside its skins that its compute speed is unaffected by network issues, and it can't reasonably affect network performance. There are notable exceptions to this broad statement, of course, particularly when malicious intent is involved.

If you were experiencing slow performance, it's more likely to be software issues than hardware. The applications being used by the users would be the place to start. Of course, if server functions are being operated on a SLOW machine, there might be some unhappy users.

Quick Launch is an Icon tray. it would be a pretty obtuse observation to find a way in which it could affect system performance.

It seems like others have the memory situation better analyzed than I can do.

But as to routers and switches, well, once again in this day and age it's a pretty obtuse discussion. But it is a fundamental truism that, by definition, switches are faster than routers. The other posters are absolutely wrong about this. I'm absolutely positive.

Routers perform the operation of moving traffic from one port to another by examining the destination IP address using software-controlled mechanisms. These mechanisms are typically run in a real-time OS on communication-specific processors using Content Addressable Memory (CAM) for cached addresses, but are software controlled nonetheless.

Switches perform the operation of moving data from one port to another by examining destination ethernet (for an L2 switch) or IP (for an L3 switch) addresses using purpose-built Application-Specific Integrated Circuits (ASICs) with on-board CAM. By definition, switches are faster than routers.

Humbly,
JR

[wreckwriter]

Routers perform firewall duties as well, switches don't. Better doesn't always mean faster. That was what I meant when I said that routers were "better".

[LarryG]

Now boys, let's play nice ...

For the record, our network looks like this:

Servers and workstations --> 10/100 switch --> router --> DSL modem

It's technically peer-to-peer, although the servers are not used as workstations and none of the workstations share any resources.

The router has a built-in hardware firewall.

We use fixed IP addresses, mainly so I can control which machines can "see" the Internet and which cannot.

But allow me to stress ... we are NOT having any network issues, are not shopping for new hardware per se, are not trying to solve any problems. The questions I'm asking are merely an attempt to check the validity of what I'm being told by this new player who has suddenly entered the scene.

[JR]

Routers perform firewall duties as well, switches don't. Better doesn't always mean faster. That was what I meant when I said that routers were "better".

Fair enough. That takes us to the esoteric arguments about what features a router has that a switch does not, or vice versa.

Here is a modest switch at the low end of Cisco's Catalyst lineup (http://www.cisco.com/en/US/products/ps6545/index.html), with MAC filtering and 802.1x authentication. Is that a "firewall"? Yes. Is that sufficient network-level security for small business? Probably. Is there some other feature offered by some router that one might want? Probably.

Nowadays the distinction between switches and routers is largely moot. I deal with this stuff quite a bit. Even the marketing guys at the large equipment manufacturers have trouble identifying themselves as the "switch" guys or the "router" guys. For example, one mfr. I work with calls the relevant division the IP Networking Division, just to cover the waterfront.

JR

[wreckwriter]

Nowadays the distinction between switches and routers is largely moot.

I don't disagree with this. Its clear you're far more up on this stuff than i am anyway

[scorrpio]

On Athlon/Duron issue: the guy is totally misinformed. Though you can blame AMD for that. For past several years, they been putting 'Athlon' tag on about every full power CPU that left their factories.

Where this 'expert' of yours got his facts wrong is that AMD's 64 bit processors - Athlon 64, FX, and X2 - come under same Athlon name as the older 32-bit T-bird and XP. Duron is a budget version of Athlon XP, and is thus a 32-bit processor.

The 64-bit hardware becomes more common, there is 64-bit version of Windows XP Pro available to take better advantage of it, and to allow 64-bit optimized applications. Those applications are primarily those that need to to a massive amount of math - scientific simulation, video processing, etc. 64 bit hardware also offers a boost when running 32 bit applications. And if your Athlons are of T-bird or XP variety, they are in same boat with Durons far as 64-bit computing is concerned.

However, it is going to take a rather long time before everyone fully migrates to 64-bit environment, and applications stop coming in 32-bit versions. In fact, right now, 64-bit computing is still in its infancy, and is primarily targeted at pro market. 64 bit drivers for consumer-level peripherals are very scarce. The only applications offered in fully 64-bit versions are also primarily pro stuff, priced in 800+ $range.

I estimate that in 2010, you'll still be getting good use out of your Durons.

[LarryG]

And if your Athlons are of T-bird or XP variety, they are in same boat with Durons far as 64-bit computing is concerned.

That's exactly what they are, and exactly what I thought (I'll go so far as to elevate thought to knew). If our Durons won't run it, our current Athlons won't, either.

In the interests of being totally objective, the matter of 32bit vs 64 bit did not specifically enter our conversation. But I have no doubt he is fully aware that all our existing AMD boxes use 32bit processors. Also, he stated that the future software would not run "... because the Level Two cache [of the Duron] is too small." That was the specific reason he gave -- the L2 cache size.

I'm not familiar with the 64bit Athlons. How does the Sempron fit into the picture? Is it sort of like the Duron was: a budget version of the full-blown Athlon 64? Reason I ask is, this guy told me the new box he built for me would have an Athlon FX57 in it, a chip that he said retails for ~$800 (but which he claimed he could get for much less). And when I right-click My Computer, Properties, Support Information, the box that opens shows "Athlon FX57 or Sempron 64" at the top. But the CPU is, without question, a Sempron. I pulled the heat sink off and looked at the chip.

We're being bamboozled, eh?