Anyone know where the SATA "controller" is on a CPU or motherboard?

I think I narrowed down my boot problem not to the boot disk but to the
SATA controller not working.

The pre-post black & white text only screen sees all 6 SATA ports as empty,
no matter how many are in use.

Only every fifteenth boot (it's getting worse) it sees the boot disk and
the pioneer built in optical disk in SATA ports 0 and 1 but even then
doesn't boot.

If it's the SATA, is there a way to overcome this?
The CPU & memory tests fine in the HP diagnostics when appropriate keys are
pressed at power up.

Is the SATA controlled on the motherboard or inside the CPU?

delvon daily wrote:

I think I narrowed down my boot problem not to the boot disk but to
the SATA controller not working.

The pre-post black & white text only screen sees all 6 SATA ports as
empty, no matter how many are in use.

Only every fifteenth boot (it's getting worse) it sees the boot disk
and the pioneer built in optical disk in SATA ports 0 and 1 but even
then doesn't boot.

If it's the SATA, is there a way to overcome this? The CPU & memory
tests fine in the HP diagnostics when appropriate keys are pressed at
power up.

Is the SATA controlled on the motherboard or inside the CPU?

https://en.wikipedia.org/wiki/Southbridge_(computing)

Rather than replace the motherboard, I'd first start with replacing the
PSU. How old is it? How overprovisioned is its load capacity (how many
excess watts can it supply for a constant load, not spurious loads,
compared to how much is currently being drawn from it)? Good PSUs are
*not* cheap. They are the lifeblood of the computer.

delvon daily wrote:
I think I narrowed down my boot problem not to the boot disk but to the
SATA controller not working.

The pre-post black & white text only screen sees all 6 SATA ports as empty,
no matter how many are in use.

Only every fifteenth boot (it's getting worse) it sees the boot disk and
the pioneer built in optical disk in SATA ports 0 and 1 but even then
doesn't boot.

If it's the SATA, is there a way to overcome this?
The CPU & memory tests fine in the HP diagnostics when appropriate keys are
pressed at power up.

Is the SATA controlled on the motherboard or inside the CPU?

The SATA controller is on the motherboard.

On older Northbridge/Southbridge designs, it's in the Southbridge.

In newer designs where the Northbridge is inside the CPU,
the SATA would be in the Southbridge called "PCH".

On motherboards with outstanding SATA setups (8 connectors or more),
an additional standalone chip is used on the motherboard.

SATA controllers may be added to a computer using add-in cards.

In the old days, we'd use a Promise Technologies Ultra133 TX2 to
extend storage capability. That had ribbon cable drives connected
to it. There would be two ribbon cable ports hosting up to four
disk drives.

If you go to the computer store today, you can find dual SATA III
port cards for a PCI Express x1 slot. I keep a spare card here that
I put in a machine occasionally (to connect a WDC drive with some
sort of SATA electrical problem).

If you have left-over expansion slots on the motherboard,
they can be used for storage cards.

On a BIOS-based motherboard (not a UEFI), low memory is
limited to 256KB for card drives. This memory area limits
how many add-in cards will work. Perhaps in the old days,
you'd add three add-in cards and the fourth one would
not be picked up because there wasn't enough low memory.
I don't know with the modern UEFI designs, whether the
starting mode of the processor is quite the same. Or whether
a more useful operating mode is used during POST.

The Southbridge would normally host a PCI bus. If the
Southbridge PCI breaks, then add-in storage cards on that
PCI bus would not work.

Both the Southbridge and the Northbridge/CPU host PCI
Express ports. There are more sources of those point-to-point
resources. If a PCI Express lane blows out (some early Nvidia
ones are prone to that, on the video slot), it doesn't
affect the other PCI Express lanes. If you blow out the
video card, the x1 slots would likely still work.

If a motherboard low voltage supply to the chipset fails
(this doesn't come from the PSU directly), it can cause
a chipset failure, and could lead to multiple kinds of ports
failing at the same time.

Some BIOS actually have adjustable voltages. For example,
due to demonstrated memory errors on this machine, I have
to bump Vnb in the BIOS by a few points, to improve memory
interface performance and stop the errors. I've been running
the stupid machine like that for years. If the CMOS battery
dies, I have to remember to put that mod back.

This is an ASM1062 based card, with an x4 connector and two
SATA ports. You might use this if you have an SSD drive in
the machine.

https://www.amazon.com/Controller-Ex.../dp/B07QGSWRM9

Whereas the more common ASM1061 card has a x1 connector, as
there are more expansion slots like it.

https://www.newegg.com/syba-sy-pex40...82E16816124045

On Marvell SATA based cards, you have to check the reviews
for transfer rate. As there was one early chip with a 300MB/sec
limitation (should have gone faster). Later ones of those
are likely OK. The quad port cards you see (real cards, not
fake 2+2 cards with jumper blocks on the card surface), those
are likely based on a Marvell controller. Eight port cards
are less common, even though there are a few chips available
with that kind of fanout. The main chip in that case, might
need a heatsink. (RAID cards with XOR chips need a heatsink
too, but stay away from the RAID cards if you can.)

You'll also need to see whether there is a convenient SATA cable
in the box or whether it's just the card. Sometimes you need different
combinations of straight, right-angle or left-angle cables to
complete your modification. Right angle connectors are good for
tray mounts that face the side of the computer case. Whereas
a straight one can be used for drives in the more normal 5.25"
bays in the front of the computer. There is room inside the
computer case, to use a straight connection. On the side mount
trays, only a right-angle connector has sufficient clearance
to the side panel sheet metal.

I've already blown out a port on my Southbridge, so I have
five left. I can't really afford to lose more than that,
as I use all of them when running backups (I back up four
drives, to a fifth drive).

Paul