Eighteen months ago, you may have done something that will bring down your computer systems tomorrow or a year from now.
During the past couple years, the makers of motherboards and memory upgrades -- for reasons of cost -- started standardising on tin plating for memory connectors, instead of the traditional gold connectors. Mixing the two metals can lead to fatal data errors.
"If you put gold-plated RAM into tin-plated slots, degalvanisation will cause the components to decay and crumble," says Jerry McCoy, owner of CRM Software, a reseller based in Salt Lake City.
The problem can occur if users move their existing gold-plated SIMMs into new tin-plated systems or if they upgrade older systems with tin-plated motherboards.
The speed of the corrosion is affected by factors including the quality of the components and environmental conditions, but generally it can start in as little as three weeks and cause problems within six months, observers say.
"There's been no problem with customers that I've seen who put old memory in," says Scott Magnes, director of sales for board manufacturer American Megatrends (AMI). "It typically takes a long time ... three to five years or so."
If a customer asks, AMI says it's not a problem, Magnes says.
Some IS managers agree.
"In my opinion, by the time the corrosion would be enough to be a problem, the system would be obsolete. We've done considerable memory upgrades and I don't think we're making a conscious effort to check for gold-to-tin contact," says Allen Skaggs, technical support manager at Ohio's Department of Human Services, in Columbus.
One IS manager, however, says he had to replace mismatched memory when it started failing after less than a year.
Most motherboards -- including those from Intel, AMI, Micron Computer and IBM Microelectronics -- are now tin-based, leaving customers with few gold-plated upgrade options, observers say.
"All of our products are tin-based. We recommend using the same type of SIMMs and don't recommend mixing SIMMs," says David Sorenson, product marketing manager of advanced systems at Advanced Logic Research. "When you use gold and tin there is some potential problem in metals corroding. But my understanding is that it evolves over time, over a few years. I've never heard of anybody having a problem."
Some vendors also say that users might not add the older gold-plated memory to newer systems because it may be slower.