SVANDUSEN Scratch Page

CPU (Processor) Testing

SVANDUSEN 19:13, 26 May 2010 (UTC)

CPUs are the "brains of the computer system. This is where all of the information and instructions are gathered from, processed, and redistributed to the other components of the system. The following will be a description of a VERY RUDIMENTARY TEST to determine the viability of a CPU to function in a system. In actuality, there are a multitude of details and issues involved that would take far more space to cover and time to perform than is practical in these circumstances. This is a very basic overview of the essentials that are necessary to get through the process. For more information please consult other experienced volunteers, instructors, or research such sources as Wikipedia or forums on Google. STEPS NOTES AND DETAILED INSTRUCTIONS Collect CPUs will accumulate in two areas: Advanced Testing Incoming Rack - there is a covered, foam lined bin on the rack labeled "Incoming CPUs".All CPUs extracted from systems by System Evaluation or other departments and CPUs that have come to the store as customer returns are supposed to be brought and deposited in this container. CPUs extracted in Advanced Testing during Motherboard triage should be deposited here as well. Receiving - there is a box on the top shelf of their rack, next to 'Unsorted Memory' labeled 'Processors'. In theory, all processors with pins are supposed to be brought immediately to us by Receiving, however, exceptions do occur. Other types of CPUs may gather there as well. At least once a day (preferably twice to three times) the contents of these collection points should be gathered and evaluated. Pre-test Evaluation and Storage Evaluate the collected CPUs as follows: 1. Socket Type Intel 478 and 775 - Retain in Pre-test Storage. AMD 754, 939, AM2/AM2+/AM3, Phenom - Retain in Pre-test Storage. Intel other than 478 or 775 (e.g.. 370, slot processors, etc.) - Automatic Recycle. AMD other than 754, 939, AM2/AM2+/AM3 (e.g., 462 [socket A], socket 5, socket 6, etc.) - Automatic Recycle. Non-Intel or AMD (e.g., Cryix, VIA, etc.) - Automatic Recycle. Non-desktop system processors (e.g., laptops, servers [Intel Xeon, AMD 940, etc.], etc.) - Automatic Recycle. 2. Obvious Physical Damage Primarily this will be bent pins. This will only occur with PGA (Pin Grid Array) processors; socket 478s, 754s, 939s, AM2s, etc. This is not necessarily a sign to recycle the processor. Many can be rescued. A determination will be made at the actual time of testing - Retain in Pre-test Storage. If any pins are broken off - Automatic Recycle. This step of evaluation is primarily to determine whether there is an inordinate amount of damage occurring prior to their arrival in Advanced Testing so that the sources can be advised and corrective steps taken. Very rarely an LGA (Land Grid Array) processor (currently this applies only to Intel socket 775) may have a deep scratch across one or more of the gold contacts on the face. This is the equivalent of a broken pin on a PGA processor and cannot be repaired - Automatic Recycle. Very, very rarely ... there will be signs of scorching; indicating that a major thermal event has taken place sometime during the life of the processor. Again, this is not necessarily a sure indicator that the processor should be recycled unless the damage is obviously severe. This is a judgment call that experience will teach - Retain in Pre-test Storage. Put the sorted processors into Pre-test Storage in TARDIS. This is basically in the same place as the tested processors; on the self, in trays or other containers, in places designated by socket type. Preparation & Testing When the is accumulation of untested processors in Pre-test Storage is sufficient to justify testing, bring the trays out of TARDIS for preparation and testing: 1. Prepare -Prepare the CPUs as follows: a. Place the Pre-test Storage tray on a work surface. b. Place a drop of solvent on the die (solid, metallic, upper surface) of each processor and smear until coated evenly. c. Leave for a minute or so to allow the solvent to work. d. Use a rag to clean thoroughly clean away all of the old thermal paste and other material from the die. e. Replace the processor in the tray and repeat until all of the processors have been cleaned. 2. Evaluate -Evaluate the prepared processors as follows: "WallTime" is frozen - The clock stops ticking ... period. This may happen very early in the testing process or may occur much deeper. One or more sticks have failed. See "Remedies". "Cached" column indicates a different total capacity than the known amount physically loaded - The total capacity of RAM indicated by this column must equal the known total capacity of the RAM physically loaded onto the board. If not ... this indicates that the system is not reading all of the RAM that has been loaded. It is permissible for the speed indicated by MemTest to differ from the speed indicated on the stick (it will simply run at a slower speed ... this is not optimal but acceptable). This may NOT be a problem with the RAM. This may be a problem with one or more of the banks on the test board. One or more sticks and/or banks have failed. See "Remedies." Remedies - This can be tedious, time consuming, and tricky, but with the technology available it is the only way. Red Screen - here there is an important clue. A new row of column headings will appear above the red area (the bottom half of the MemTest screen). Only Test, Pass, and Failing Address are relevant here. Test and Pass will indicate at what point in the testing process the failure occurred. If it occurs early (eg. pass 0, test 1), all well and good. If it occurs deeper in the testing process, it may be that a failing stick will begin testing well and then fail, making it more difficult to identify. Failing Address is in two parts which indicate the pattern (not relevant here) and the point in the total capacity at which the failure occurred. Moving from outboard to inboard, subtract the capacity of each stick from the total until you are in the range at which the failure occurred, eg. four sticks of 256 MB RAM for a total of 1 GB have been loaded. A failure occurs at 368.2 MB on pass 0, test 1. The failure has occurred between 512 MB, and 256 MB. Subtracting 256 MB for each of the two outboard sticks (banks 3 & 2) leaves 512 MB. The failure occurred at a point below this capacity. The failure occurred at a point greater than 256 MB, the capacity of the first inboard stick (bank 0). Therefore, it is most likely that the stick in bank 1 is the stick that failed. Power off at the switch on the power supply Remove the suspected stick. Restart the testing process and monitor MemTest again for failures. No Video or Cached column indicates lower total capacity than physically loaded. This may simply be a matter of the sticks not being seated properly, or the system does not recognize the RAM in the order in which it was loaded, or it has compatibility issues with brands, latency, etc., OR it has some other problem all its own and refuses to give you any indication as to what it might be. Power off at the switch on the power supply. Remove and re-seat all of the sticks. Change the order, re-balance the load across the channels, reverse the channel position by pairs, etc. Restart the test process and monitor MemTest again for failures. WallTime freezes or the location steps for Red Screen, No Video, or Cached column differential don't resolve the issue. Unfortunately ... it's strictly trial and error from here on. Power off at the switch on the power supply. Remove the suspected stick or sticks, singly or in pairs. Restart the testing process and monitor MemTest again for failures. Repeat as necessary until issues are resolved. If a bad bank or other system failure is suspected for any reason - Power off at the switch on the power supply. Remove all RAM sticks. Test each bank with a known good RAM stick. If all banks pass, all well and good. If not, power down, remove, stick or sticks, mark the suspected bank or banks with a label, and notify an instructor. If something other than a bad bank or banks is suspected, ie. video or network issues, ask an instructor. 6. For the duration of the testing process - Check on the progress of the testing process. The time necessary to complete the testing process can vary greatly, depending on the capacity and speed of the RAM that has been loaded, the FSB (Front Side Bus) speed of the CPU or other factors specific to the test board. The time can be less than one hour, with low capacity and/or high speed, or can take an incredibly long time with high capacity and/or low speed (eg. 2 GB of SDRAM at 133 MHz can take nearly 24 hours). Generally an average load of around 1 GB of DDR or DDR2 will take between 2.5 and 3.5 hours. A complete testing process consists of three passes, labeled 0-2. Each pass consists of 'eight tests, labeled 1-8. MemTest will continue to run indefinitely until is manually discontinued. If the pass number is 3 or greater, the testing process is complete. Watch for indications of failure, as indicated above, and correct as necessary. 7. Repeat these steps for each test board as long as there is RAM to be tested. 8. Do NOT load any boards after 5:00P. Label & Route After the testing process has been completed, label and route the tested RAM as follows: 1. Unload the test boards - . Power off at the switch on the power supply. Remove all RAM sticks and take them to the table to be labeled. If possible, remove any old, handwritten labeling to avoid confusion. 2. Label as follows: SDRAM - capacity and speed only. Eg. 256/133. DDR & DDR2 - type and capacity and speed. Eg. DDR2 512/667. DDR and DDR2 have more subtle visual cues (other than the label) and can be easily confused by after-testing users such as build. Therefore, it is highly advisable to make them as distinguishable as possible. Kit of 2 - Label each stick with its true capacity and speed. Eg. a 1GB kit of 2 - each stick would be labeled as 512 MB with the speed. If you have both halves of such a kit, make a small nonstick paper strip label, write "Kit of 2" and "xxx MB (or GB) each" on it, wrap it around the kit, and rubber band it together. 3. Route as follows - The two boxes on the table labeled, "Tested RAM SDRAM & DDR" and "Tested RAM DDR2" - Place the vast majority of the labeled RAM in the appropriate slots in these two boxes (see Store for exceptions). This will be harvested regularly by build and occasionally by the store to fill their needs. TARDIS - The boxes on the table will populate quite rapidly. As they fill (usually once a week or more), empty the slots into the appropriate static free bags in the blue bins on the shelf in TARDIS. As the bags fill, tape them shut and place them in the RAM Overstock bin on the top shelf. Replace the bag with an empty one labeled with type, capacity, speed (in MHz) and PC or PC2 code (PC 2100, PC 2700 ... PC2 4200, PC2 5300 ... etc.) These will be harvested by build and the store to meet their needs. Store - Some tested RAM should be taken directly to the store (do not put in the outgoing "Store" box on the rack shelf next to the TARDIS door). SDRAM - 1GB/133 DDR - 1GB/any speed. 512/400 - pairs (or more ) of quality brands (Hynix, Nanya, Samsung, etc.). Leave singles in the box for build. DDR2 - 1 or 2 GB/any speed. 256 or 512/667 or higher. All PAIRED & BUNDLED Kit of 2 sets. Any sticks, paired or not, any capacity and speed, with "heat spreader" technology ... metal plates over the embedded chips that run the length of the stick on one or both sides. End of DAY POWER OFF ALL TEST BOARDS AT THE SWITCH ON THE POWER SUPPLY WHETHER THE TESTING PROCESS IS COMPLETE OR NOT!