I believe it is about 1.5 to 2 inch difference. But I suppose some standard plates may be different. I would recommend staying with 315 for this week. Overall, better to play it safe with the deadlift.
Well, I should ask, do you mean standard Olympic plates as compared to bumpers or actually standard plates with the old 1 inch hole?
I lift with the old 1 inch bar and standard plates.
James 1:16-17 ESV
Do not be deceived, my beloved brothers. Every good gift and every perfect gift is from above, coming down from the Father of lights
With God's help...Mens sana in corpore sano