Desktop Buyers Guide - Choosing a CPU and RAM
The “incredible graphics” and “giant memory” you see on inserts or advertisements mean something after you purchased the item. Of course a meaning negative to your wallet. Only until you know what to look at and ask the right questions you can save yourself from wasteful spending.
The golden rule that applies to shopping also applies to electronics: Determine your needs first. If you want a desktop computer for your office productivity tasks, surfing the Internet, listening to music, oe even watching movies, you do not need the fastest computer around. On the other hand, if you are a serious gamer or a technically-oriented person who loves overclocking, you will not benefit much from an office-type computer.
The sellers love to be proud of the computer’s processor (Central Processing Unit – CPU) speed. However, for your daily office and multimedia tasks (I will call them “office-type computers”), you only utilize a fraction of this speed and the remaining part just has a marginal effect on performance. So, you will not need the latest, fastest, greatest CPU, but an entry-level one. If you are into 3D design or do some other intense number crunching, then you have to consider the number of cores on the processor**,** as well as the speed. A low-speed CPU speed with many cores will not deliver the same performance as a faster but a dual core processor in most cases. If you are working with high-performance applications, have several windows open and many tasks running in the background, then it is better to think about a quad-core processor. If not, a dual-core will do fine.
RAM is one of the real issues to know. A 32-bit operating system can not work with more than 4 GB of RAM, because it can address only 232 of space, which comes near to 4 GB. There will be deductions from this amount, because of some addressing issues, like:
- On board graphics adapters will “steal” some space from the RAM. This is what I noted above: if you use 4 GB with an on-board graphics card, it will eat up it’s memory from your overall RAM. If your on board graphics can use 1 Gigabyte (say 1024 Megabytes) of memory, and the onboard graphics have 128 Megabytes of their own memory, the remaining 1024 – 128 = 886 Megabytes will be stolen from the main memory. So, if you have 4 Gigabytes (4092 Megabytes) of RAM, 4092 – 872 = 3224 Megabytes will be available.
- Today’s modern graphics cards require address space for their on board memory. Meaning that, if you have a graphics card with 512 Megabyte memory, then in your operating system you will see 4092 – 512 = 3584, or about 3.6 Gigabytes in your operating system. So, 4 GB is not what you will get. Three and change is still better than two though.
Normal office applications, web surfing, and watching movies can be done without problem on 2 GB of ram. Gaming and multitasking benefit from 4GB, even if it isn’t all in usable. Computers with 64-bit operating systems can see all 4 GB of memory and more.
On the next page: Grapics Card, Motherboard, and Sound Card Selection
Next comes the graphics card. Again, your needs will dictate: if you need an office-type computer, then even on-board graphics will do fine; if you want further graphics speed, then you have to consider a separate graphics card. Choosing one is a vast issue; see this article on choosing a graphics card. Nowadays there are also “hybrid” options, meaning that you can have both on board graphics adapter and a separate one. The system uses the on board one to save power in normal tasks and uses the separate one together with the on board one for demanding tasks.
Make sure you get a card or computer with a DVI and/or HDMI output. Even if your monitor does not support these connections, you can use an inexpensive DVI to VGA adapter or cable for the time being. In this case, it will be an investment for the future: when you replace your existing monitor with the one that has DVI/HDMI input, you will get a clearer picture. The difference between and tips for uppgrading VGA to DVI are here.
The other important factor is the motherboard (also called mainboard) which is basically the hub to which all the computer’s parts are connected. When you decide on the computer to buy, never underestimate the motherboard; insist on learning the brand. The dominant players in the motherboard market are Asus and Gigabyte, with MSI and Foxconn trying to make their ways to the top. Choose a motherboard from one of these brands.
Learn the maximum frequency that the motherboard supports for the Front Side Bus (FSB). If you choose an Intel Core i7 processor or an AMD, this issue does not matter, because these processors do not have FSB. Make sure that the CPU, the motherboard and the RAM can communicate at the same speed (frequency). If your processor supports 1333 MHz, your RAM 1333 MHz, and your motherboard only 1000 MHz, then your whole system will work at 1000 MHz. The rule that a chain is as strong as its weakest point holds true here. You can find more tips in this article about choosing a motherboard.
If you are done with the main components, then you can consider the sound card. If you are not an audiophile and want a basic sound system, then you can go with the onboard one. However, if you will watch DVDs from your computer and have/will have 5.1 or 7.1 speakers, then make sure that the onboard sound supports these surround speakers. For more clear sound, go with a sound card.
Next Page: Internet, Expansion, Conclusion
Next is connectivity. Nowadays the standard is the 10/100/1000 Megabit (or Gigabit) Ethernet adapter. Make sure that the computer has one. You will need it to connect and configure most broadband modems/routers.
Also do not forget that you can have a wireless card for your desktop computer but it is very unlikely that you will find this in low end computers. If you want the wireless connectivity, ask the salesperson for the additional costs. If you already have a wireless modem at home, try to choose the same brand for the wireless card (you can take advantage of the increased speed/coverage if offered by the wireless router/wireless card vendor. For exampla US Robotics have Super G wireless connection that offers 128 Megabit per second, twice of the Wireless G standard, but both your wireless router and your wireless card must support the Super G.)
More importantly, you need to get the most modern wireless standard you can aford. A and B are out of date and will be quite slow compared to G, and N is the fastest. The different standards are compatible, but you are limited to the slower standars speed when mixing.
And last, check the expansion possibilities: Can you add a TV card? Can you add another hard disk? Can you add a Blu-Ray drive in addition to the existing optic drive. Card readers are often built into the computer. A drive bay ard reader can be found for about USD 10, so don’t fork over too much extra money for a computer with one built in.
If you are done with all the above, which are the essentials of your computer, then carry on and check its connections: DVI/HDMI ports, the number of USB ports, any FireWire/eSATA slots, any spare 3.5” slots, any spare PCI slots? You can learn about all the different connectors used by a computer here.
In this article I tried to give you the key points for choosing the right desktop for you. It is not possible to include every possibility that comes with a desktop computer. If you are an audiophile requiring pure, clear, sound, then your choice of sound card is more important than it would be to say, a gamer. The gamer will prefer better and fluent 3D graphics over the best sound, and spend her money on a graphics card instead.
Finally, we come to the question of an OEM brand name computer, or a custom built one. If you are confident that you can research all of the parts you’re going to need and put them together yourself, or find/hire someone who can, then go with a custom build. Building your own PC can be a very rewarding activity, personally and finacially. If you are less confident, OEMs offer warranties and tech support, which also have to be considered when buying. Of course, the business that assembles a custom computer may offer warranty and tech support, but often for an additional fee.