Do all mobo-integrated audio/video/lan solutions steal processor cycles?

[Caiwyn]

Does the use of a motherboard's integrated audio, video, or lan take up more processor cycles than PCI or AGP components of similar capabilities? I know a good video card will almost always perform better than integrated video, but let's say hypothetically that my two options consist of an older video card, or a newer integrated solution, and let's assume that they both yield the same quality graphics. Will using integrated video slow things down at all? What about integrated audio or lan?

Basically, I'm trying to decide whether or not to get a CNR LAN adapter for my 815EP mobo, or stick with a PCI network card. I obviously don't want to go with the CNR solution if it's going to eat even just a few more processor cycles than that PCI NIC would, but if that's not the case, I find the CNR solution appealing.

 

[Noriaki]

No not always.
I can't commment on the i815E because I'm not sure exactly how Intel's I/O hub works.

But for example, I have two boards right now
MSi K7 Master: Onboard audio is the Via AC97 Software CODEC.
Asus A7A266: Onboard audio is a PCI C-Media 8374 sound chip.

In the case of the K7 master it uses CPU cycles, the A7A is a PCI chip that is soldered to the motherboard instead of a PCI card, but it's still a hardware sound chip.

 

[Caiwyn]

Ah, that's what I kind of figured. Thanks for the info!

Now then, does anybody know about the 815EP-based motherboards in particular? They utilize a CNR slot that you can plug an adapter into which utilizes the chipset's built-in LAN functions, but I have no idea whether it's going to steal more processor cycles than a PCI NIC would. Anybody got a clue?

 

[Caiwyn]

*bump*

No love from all you hardcore techs out there? Anybody know about the 815 chipset and CNR slot network adapters? I'd really appreciate the help...

 

[nam ng]

<< Does the use of a motherboard's integrated audio, video, or lan take up more processor cycles than PCI or AGP components of similar capabilities? >>



They all do unless they're crossbar design, then its dependent on how complete a crossbar design they're.

In conventional design all device resource accesses are serialized, one device at a time, IE... master and slave devices on a single IDE channel. If the CPU performing a memory read, despite the fact of unable to use up all the bandwidth of 128bit DDR memory, while the CPU is performing it no other devices can access the memory.

Crossbar leveraging excess unused bandwidth to allow simultaneous access by other devices. This is the very thing, which make crossbar most useful. Simultaneous data access is the prominent crossbar feature, added bandwidth efficiency is the positive side effect of simultaneous access.

 

[AndyHui]

In the case of the i815E/EP chipset, it doesn't really steal processor cycles, as an Intel PRO 100+VE has been integrated into the ICH2 (South bridge) of the chipset. The CNR module is merely supposed to provide an RJ-45 plug.

As far as integrated video goes, it may take a few extra CPU cycles depending on how well the manufacturer has written the BIOS, but generally integrated video eats up memory bandwidth from the system rather than stealing CPU cycles.

 

[nam ng]

<< but generally integrated video eats up memory bandwidth from the system rather than stealing CPU cycles. >>


If any other devices forcing the CPU to be idle while using system resources, I considered it stolen/wasted CPU cycles.

 

[Caiwyn]

Andy, thanks for the info on the chipset. I do appreciate it.

And thanks everybody else for the advice. Sounds like the CNR adapter won't hurt, and I've got a decision to make!