---

@WM1000wrote:
And there is two 2gb 667mhz dimms and two 1gb 800mhz dimms

---

1. Which pair was originally installed ... when it was working and not BSOD-ing?

2. Are they both matched pairs?

And there is two 2gb 667mhz dimms and two 1gb 800mhz dimms

---

@WM1000wrote:
So I upgraded my Optiplex 760 to 6gb of ram. And now when I try to run windows 7 or install it it bsods at starting windows screen

Stop code is
0x0000007f (0x0000000000000008, 0x0000000080050033, 00000000000006f8, 0xfffff800002cb600)

---

Test ram (outside of Windows) with both

1. ePSA Diagnostics (F2 or F12 on boot)

2. www.memtest86.com

You should get ZERO errors with both.

The original dimms were all 1gb kingston 800mhz in all four slots.

The new dimms I ordered were two apacer 2gb 667mhz

---

@WM1000wrote:

The original dimms were all 1gb kingston 800mhz in all four slots.

The new dimms I ordered were two apacer 2gb 667mhz

---

So, for starters ... from that simple comment, it looks like your machine needs 800mhz DIMMs, and you installed new 667mhz ones instead. That doesn't sound right.

Second, generally ... it helps if all the DIMMs are at least the right speed (down-clocking aside).

How are you doing on those tests?

Ok so after the test was done it said "pass complete,no errors, press esc to exit

And I never expected errors on Windows if I just mix ram speeds. Because I mixed 1333mhz ddr3 ram and 1600 mhz ddr3 ram on a win 8.1 laptop and it didn't bsod.

And if I need to use all same speed, should I just order the same apacer dimms to fix it or do I need to use original ram and buy 800mhz ddr2 sticks to pair with that ram.