Intro to Computer Systems

Chapter 12: System Integration

Cascade Effects

As the components in a modern computer system work collaboratively to provide their best performance, there are often knock-on effects from selecting a particular component. There may be many reasons for this, be they:

Knock-On Effects of Hardware

To summarise how each subsystem may (or may not) affect the others; many of these dependencies work both ways.

CPU

CPU selection's effect on...
Memory

The CPU's integrated memory controller will determine memory technology and allowable speed ratings.

Server and workstation platforms may support (or require) specialist memory such as Registered and/or ECC memory.

Motherboard and Chipset

The CPU must be compatible with the chipset of the chosen motherboard.

The motherboard's socket must be physically and electrically compatible with the CPU. (Some CPUs may not be compatible even if the sockets match, due to power requirements.)

Graphics and Display
The CPU may have an integrated graphics processor, which could be used.
Mass Storage
No significant effect.
Expansion Options
May determine expansion technology for high-speed subsystems (e.g. PCI Express connector intended for a discrete graphics card)
Power Supply
Often no significant effect; high TDP CPUs may require special requirements on voltage rails, or additional power connectors.
Enclosure and Cooling
A high TDP CPU would not be appropriate for enclosures that are very small or have poor cooling design.

Memory

Memory selection's effect on...
CPU

Slower memory modules may pose a bottleneck for some specific computation tasks.

Motherboard and Chipset

The motherboard will determine how expandable the memory is - e.g. the number of memory slots available for current (and future) use.

Graphics and Display
Interleaved memory (dual- or triple-channel) will optimise the performance of an integrated graphics system.
Mass Storage
No significant effect.
Expansion Options
No significant effect.
Power Supply
No significant effect.
Enclosure and Cooling
No significant effect.

 

Motherboard and Chipset

Motherboard/chipset selection's effect on...
CPU

The CPU's must be physically and electrically compatible with the motherboard socket and chipset.

Memory

The motherboard will determine how expandable the memory is - e.g. the number of memory slots available for current (and future) use.

Graphics and Display

The motherboard may not have a high performance expansion slot (e.g. PCIe 16x) exposed to the user, in order to install a discrete graphics card.

In some cases, the motherboard must explicitly support running multiple discrete graphics cards for high performance systems.

Mass Storage

The motherboard model will determine how many of the chipset's mass storage interfaces are exposed to the user, be they SATA ports or mSATA slots.

The motherboard will determine the interface specification, if using the onboard features.

Higher end motherboards and chipsets may make available chipset-based RAID features.

Expansion Options
The motherboard will determine how many expansion slots for various devices are available: expansion cards, memory slots, internal headers for USB, FireWire, etc.
Power Supply
No significant effect.
Enclosure and Cooling
The enclosure must be large enough to fit the motherboard; e.g. a full-ATX motherboard will not fit into a micro-ATX case.

 

Graphics and Display

Graphics/display selection's effect on...
CPU

No significant effect.

Memory

Integrated graphics will "steal" some system memory for its own use.

Motherboard and Chipset
The motherboard may not have a high performance expansion slot (e.g. PCIe 16x) exposed to the user, in order to install a discrete graphics card.
Mass Storage

No significant effect.

Expansion Options
Low-end discrete graphics cards may not allow future upgrades to a multiple graphics card configuration.
Power Supply
High-end discrete graphics cards will have heavy power requirements, calling for very strong voltage rails and one (or several) special power connectors just for the graphics card.
Enclosure and Cooling
A small form-factor, or poorly ventilated enclosure may not offer enough cooling for high end discrete graphics.

 

Mass Storage

Mass storage selection's effect on...
CPU

No significant effect.

Memory

No significant effect.

Motherboard and Chipset
No significant effect.
Graphics and Display

No significant effect.

Expansion Options
No significant effect.
Power Supply
Running a large number of mechanical hard disks will put pressure on the power supply upon startup; can be remediated by a strong power supply, or preferably a staggered spinup of drives.
Enclosure and Cooling
No significant effect.

 

Expansion Options

Expansion option selection's effect on...
CPU

No significant effect.

Memory

Having more memory slots provides greater headroom for upgrading memory in the future, without having to discard the existing memory modules.

Motherboard and Chipset
A need for significant expansion possibilities will limit motherboard selection.
Graphics and Display

There may not be a high performance expansion slot (e.g. PCIe 16x) exposed to the user, in order to install a discrete graphics card.

Mass Storage
Many high-end RAID controllers use PCI Express x4 or x8; low end systems may not have this type of slot.
Power Supply
A system that actually makes use of several expansion interfaces may put unique pressures on the power supply (depending on the devices added to the system).
Enclosure and Cooling
No significant effect.

 

Power Supply

Power supply selection's effect on...
CPU

A low-power power supply may not provide enough current to run high-TDP CPUs.

Memory

No significant effect.

Motherboard and Chipset
No significant effect.
Graphics and Display

A low-power power supply may not provide enough current to run high-end discrete graphics cards.

Mass Storage
Low-power power supplies may require the use of staggered spinup, if several mechanical disks are present.
Expansion Options
No significant effect.
Enclosure and Cooling
No significant effect.

 

Enclosure and Cooling

Enclosure and cooling selection's effect on...
CPU

The heatsink/fan units available to fit the enclosure may not provide sufficient heat dissipation for higher TDP CPUs.

Memory

No significant effect.

Motherboard and Chipset
Small enclosures (eg. micro ATX) will not fit larger motherboards.
Graphics and Display

A slim enclosure may limit discrete graphics cards to low-profile models, which are often not available in high end configurations.

Mass Storage

The enclosure will determine how many internal mass storage devices will fit.

The thermal design of the enclosure will affect the long-term reliability of mass storage devices with in it.

Expansion Options
The enclosure may limit the number of expansion slots that are exposed to the outside. Slim enclosures may limit expansion cards to low-profile models.
Power Supply
The power supply must fit inside the enclosure. Similar to motherboards, there are a number of power supply form-factors, which often correlate to specific enclosure sizes.