Two leading chipmakers have been targeted as part of a US investigation into alleged Static Ram (SRam) price fixing.

Samsung and Cypress said that they will be cooperating fully with an investigation by the Antitrust Division of the US Department of Justice. 

SRam is faster than DRam and is most commonly used in CPU caches and memory buffers for hard disks and CD-Rom drives. DRam is the form of memory most commonly used in PCs.

The investigation is unrelated to a previous DRam price-fixing scandal in which Samsung was alleged to have been one of three manufacturers involved in a scheme to inflate the price of DRam. 

Samsung agreed at the time to pay a $300m fine, and several employees faced criminal charges.

Earlier this year, seven memory manufacturers were sued by a group of 34 states in the US for price fixing. Neither Samsung nor Cypress was named in that case.