Trouble with SPI interfaced SRAM chip

Using Arduino Storage
15

with:
CS pin 8
SPI_CLOCK_DIV2
SPI_MODE0
and no delayMicroseconds()
and no pinMode(10, OUTPUT);

every thing works fine with even shorter wires (don't use jumper wires with SRAM, with EEPROM OK, at least for me)
64K bytes written in 1.2 sec (in BYTE mode)
64K writes and 64K reads 100 times with different data each time and no fails
64K reads and writes in SEQUENTIAL mode:
write time= 128 mSec
read time= 128 mSec
no fails - I claim done