Why don't laptops have an external PCI-port?

[Menigmand]

I've been thinking about this for a long time: Why don't laptops simply include an external PCI-slot, so we could buy a decent graphics card and slot into the back of the machine while gaming, then remove it when we need to go somewhere with the laptop?

I know desktop GPUs use a lot more power, but this would be no problem while gaming at home with the laptop plugged in.

Heat wouldn't be a problem either, the graphics card would be in open air, sticking out of the back of the laptop. It would cool itself by its own fan.

So why not? I'm sure there's a good reason, I just don't know it - yet

 

[Someone Somewhere]

Firstly, I would imagine you're thinking of an ePCIe port, not ePCI. Very few GPUs use PCI now.

Firstly, you'd need one hell of a power adapter to power a decent GPU - a 7750 uses more power than many low-end laptops. It would have to have it's own power supply.

Then there's the mess of connecting it to the internal display etc - Optimus/Switchable Graphics is a pain now, imagine if it had to support hot-plugging too.

IIRC there were a few docking stations that had internal GPUs a while back, but they were proprietary. They seem to have gone out of fashion now, though.

 

[USAFRet]

I've been thinking about this for a long time: Why don't laptops simply include an external PCI-slot, so we could buy a decent graphics card and slot into the back of the machine while gaming, then remove it when we need to go somewhere with the laptop?

Because there isn't a market for it. The number of people who would pay extra would not justify an entire new design and line of laptops.
Case, PSU, BIOS, would all have to be different.

People that are that concerned about that level of gaming performance would just buy/build a desktop.

 

[Menigmand]

Because there isn't a market for it. The number of people who would pay extra would not justify an entire new design and line of laptops.
Case, PSU, BIOS, would all have to be different.

People that are that concerned about that level of gaming performance would just buy/build a desktop.

But then why are people ready to spend lots of money for gaming laptops with a very inferior GPU built inside the chassis? Surely it would be easier to just add a port than to cram the GPU inside the laptop, with extra cooling fans, heat-pipes etc..

 

[Menigmand]

Firstly, you'd need one hell of a power adapter to power a decent GPU - a 7750 uses more power than many low-end laptops. It would have to have it's own power supply.
Then there's the mess of connecting it to the internal display etc - Optimus/Switchable Graphics is a pain now, imagine if it had to support hot-plugging too.

About power, I suppose the GPU could just have its own power supply like you suggest. The laptop could be made much slimmer, quieter and run cooler if it didn't have to carry the GPU inside the cramped case.

The laptop wouldn't need to support hot-plugging or switchable graphics, it could just do a quick test during POST to see if an external GPU had been connected or not.

I don't see why this would be any different than having, say, two HDD in my computer, then taking one out - the computer would start up, but only show one disk available. Then if I put the other HDD back in some days later, it would show up and work as normal.. The difficulty of switchable graphics is to do this on the fly, but that would not be needed in this case.

 

[USAFRet]

Because there isn't a market for it. The number of people who would pay extra would not justify an entire new design and line of laptops.
Case, PSU, BIOS, would all have to be different.

People that are that concerned about that level of gaming performance would just buy/build a desktop.

But then why are people ready to spend lots of money for gaming laptops with a very inferior GPU built inside the chassis? Surely it would be easier to just add a port than to cram the GPU inside the laptop, with extra cooling fans, heat-pipes etc..

Perhaps because they don't fully realize the limitations of what they are buying?

If there were a business case for such a laptop, someone would be selling it.
People buy laptops for portability. Hanging a big honking graphics card off the side or back removes that function. Might as well get a desktop for gaming at home, and a cheap laptop for portability.
I could see a docking station, maybe. But now you've just added $300 or more to the retail price.

And the laptop would still have to have onboard graphics for use when the PCI-E card is not there.

 

[Menigmand]

Perhaps because they don't fully realize the limitations of what they are buying?

If there were a business case for such a laptop, someone would be selling it.
People buy laptops for portability. Hanging a big honking graphics card off the side or back removes that function. Might as well get a desktop for gaming at home, and a cheap laptop for portability.
I could see a docking station, maybe. But now you've just added $300 or more to the retail price.

And the laptop would still have to have onboard graphics for use when the PCI-E card is not there.

The laptop would not come with a big GPU, just with a port so I could buy my own and plug it in for gaming. It would not make the laptop less portable, I would just remove the GPU when I needed to take the laptop with me.

Also, all modern laptops now have a basic GPU in the CPU, so no problem there either.

But I guess that at the end of the day, you're right that if there were a business case for this thing, somebody would be selling it. It just baffles me that people think there's a business case for an external thunderbolt box at a huge cost and low performance, while a basic plug-in port directly into the laptop's motherboard apparently gets overlooked.

 

[Menigmand]

Well, doesn't seem like we're getting close to the definitive answer to this. So I'll just say thanks for replying both of you. Since you both had good points, I will choose the best answer based on who replied first.

 

[Someone Somewhere]

I think it would need some form of switchable graphics - how many times have you unplugged an external HDD without telling it to remove properly?

Also, PCIe isn't meant to be frequently plugged/unplugged. You'd need a separate connector, at which point you probably will need a box of some sort.