In the last article we looked in depth at the heart of the PC build:
- The CPU (processor)
- The Memory (RAM)
- The Motherboard (main board)
Now we will look at the remainder of Efficiency Heating
Coolingthe PC:
- The Storage subsystem (hard disk or HDD)
- The Graphics Processor (GPU)
- The Case
- The Cooling (HSF or heatsink & fan)
Design…Select…Standardise…Optimise and Build… The Storage (hard disk drives)
When you save your work, run an application or game, stream or encode to disk or in any other way require to access to or from the permanent storage your disk subsystem offers you are constrained by its performance. The storage system is almost the only mechanical system within the computer (although this is changing now with the advent of Solid State Drives, SSD’s). Data is stored on a hard drive magnetically and arranged in concentric circles around the disk from the centre to the edge. Therefore if your computer needs access to data at one end of the disk and then the other the drive has to physically move the head backwards and forwards, and wait for the disk to spin around to the right location to begin the read or write process. The time taken to do this is known as latency, and the average time to move the head to any given point and read data is given as Average Seek Time (usually in milliseconds, ms).
Manufacturers provide spin speed and average seek time data with their drives. In addition all drives have an onboard memory cache that the drive software uses to intelligently store previous (or read ahead) read requests so that it can almost intelligently pre-empt fetching of the data you want read. Data can then be quickly retrieved without requiring the disk to move the head. The other significant factor in drive performance is having as big a possible pipe (i.e. bandwidth) between the drive and the CPU to make sure that as soon as the drive has data available it can