Ask Dan: GeForce 6100 speed and "x1" mode?

Date: 4 March 2007
Last modified 03-Dec-2011.


Just a question about the main board in Aus PC Market's "Simple Black AM2 PC System".

What are the graphics like? I plan to use the system for emails, word processing and Photoshopping.

If the graphics aren't up to scratch, I am able to chuck a GeForce 7300 or something in afterward, aren't I?

The page for the motherboard says "PCI-E x16 slot (works in x1 mode)". What does "works in x1 mode" mean?


Every PC graphics adapter, separate or integrated, has for many years now been more than fast enough for all 2D applications. A seven-year-old PC with an integrated graphics chipset may be sluggish if you're doing desktop publishing work on it at 1600 by 1200, but the limiting factor will be its old CPU (and probably also a lack of RAM), not its graphics adapter, even though that adapter is far slower than today's integrated adapters.

The integrated GeForce 6100 on the Gigabyte GA-M61VME-S2 in Aus PC's little black computer [that board's been changed now for something better] is actually pretty decent for 3D, by the standards of such things. It won't cut it for brand new 3D games, but will give a pretty good account of itself in games that're a year or three old. If you want to play Half-Life 2, for instance, a 6100 will do quite well at 800 by 600.

If you're not playing 3D games, of course, you won't care either way.

The "works in x1 mode" part means you can plug a PCIe x1 card into the PCIe x16 slot on this motherboard if you want to. This is the case for all normal x16 slots, but the dodge here - one which is so underhanded that I originally got it wrong here, and had to be set right by readers - is that this mobo's "x16" slot is x16 in size only. It's only actually got one PCIe "lane" connected to it, so it only ever works at x1 speed, and cannot run x16 graphics cards at full x16 speed.

Gigabyte provide a (tiny) PDF here that lists the rather specialised collection of video cards that they promise will work in one of these hybrid x1/x16 slots. For anything else, you're on your own.

There's no underlying technical reason why a brand new super-fast x16 card won't be able to work at mere x1 speed. Technically, PCIe devices are meant to just run as fast as is possible for the slot you've installed them in, as has been discovered by many people with dual-x16-slot motherboards who've set the board up wrong, or installed their single graphics card in the wrong slot, and run it at x8 speed by mistake.

And, furthermore, bus speed doesn't actually have nearly as much impact on 3D performance as you'd think. If a card's out of onboard memory and has to move lots of data through the bus it's connected to while you're playing a game then performance will always be lousy; bus speed merely helps to determine how lousy it'll be. So a fast card with lots of memory running in x1 mode should, in theory, still work pretty well.

But if a given card simply refuses to run in x1 mode, which I'll betcha at least some new and exciting cards will, then you're out of luck.

God, this sort of thing annoys me. There an x16 slot is, plain as day, except it's not an x16 slot - it can just physically accept x16 cards. Down the road, people who buy these kinds of computers will decide they want to play new games and buy a nice cheap modern video card that promises to allow them to do so and then, quite possibly, be completely bloody screwed.

Why do they even make the damn slots x16-shaped? What are they thinking? OK, this is a budget board and lets you assemble a highly capable little computer for a very reasonable price, but surely they could make it a tad cheaper again if they installed a smaller, less misleading slot connector there.

All of this video card talk does not, of course, matter if you don't actually intend to add a faster graphics card. The actual slot count may matter, though, seeing as this little motherboard only has that one PCIe pseudo-x16 slot, one normal x1 slot, and two PCI slots.

All of the integrated stuff means that most users won't need to add any more cards to a computer like this, but it's nice to know you can if you need to, even if you can't add a proper video card and have it work as advertised. Every slot still counts, for little MicroATX motherboards.

The Cooler Master Centurion case Aus PC picked for this particular PC, for instance, has room for four 5.25 inch devices and four 3.5 inch ones. But the motherboard only has two SATA connectors and one PATA, for a maximum of four devices.

So to add more internal drives, you'd need another controller card, and could opt for a very cheap PCI one or an almost-as-cheap PCIe x1 one, which will be a bit faster, but probably not enough to be noticeable.

You can also get PCIe x1 800 megabit per second FireWire cards now, which is great if you want really fast external storage. Or if you want to connect any FireWire devices to this particular computer, since the motherboard for this PC has no FireWire ports of its own, just USB.

(That's a cost cutting measure of which I don't disapprove; FireWire ports are pretty standard equipment for basic PCs these days, and they almost always seem doomed to sit there empty for the computer's entire lifespan.)

There are also genuine actual x1 video cards, with just the teeny little x1 edge connector and not the normal-length x16 one, but those are only of interest to people who want to add another monitor or two on the cheap, or who got suckered into buying some lousy brand-name box with a "PCIe x16" video adapter that's (a) integrated into the motherboard, with no slot, and (b) horribly slow for 3D.

That same scam was run on people back when AGP was new and exciting. It's technically still AGP graphics if it's built into the mobo, but most people do kind of expect there to be an AGP slot somewhere in their "AGP" computer. Just as they expect an x16 slot to be able to run at x16 speed.

There's a precedent back in the AGP days for my grumbling about x16-that-isn't-x16, too. AGP didn't just go through a few speed bumps over its life, but also changed signalling voltage, which also created compatibility problems.

At least, though, AGP slots are physically keyed so that (in almost all cases...) you can only physically plug a card into an AGP slot in which it will work.

These cheap "x16" motherboards don't even seem to do you that courtesy.

UPDATE: A scant day after this page went up, Aus PC Market have swapped out the standard motherboard for this system for an Asus board with a proper x16 slot (and FireWire!), which costs a whole six Australian dollars extra.

I think that's a good choice, and a good deal.

Shoppers from Australia and New Zealand can buy Aus PC Market's Simple Black AM2 system from Aus PC Market.
Or customise it beyond recognition.
Click here to order!