On Jan 5, 2018, at 23:49, Luke Kenneth Casson Leighton lkcl@lkcl.net wrote:
On Sat, Jan 6, 2018 at 6:35 AM, Richard Wilbur richard.wilbur@gmail.com wrote:
So the trick is how to choose a faster chip and integrate successfully into a system running at lower speed than it is specified for?
yyup. have to use the 1800mhz 1.5v x8 DDR3 IC, which fortunately happens to be down-compatible with 667mhz. the 1.35v DDR3L variant of the same chip is *not*.
Your changes to the power supply capacitors and vias should help accommodate faster edges, etc. from the faster chips.
still, i cannot risk just relying on one possible DDR3 IC, so i will have to source 1600mhz as well... and also last resort a 2gigabit IC which will total, qty 4, only 1GBYTE of RAM.
the budget's fixed... it's just the way it's going to have to be. make adjustments that fit within the budget, end of story.
Here's hoping the faster ones fit the budget and the circuit as I'm a big fan of providing as much RAM as possible!